Publications

thermoplasma acidophilum: intracellular ph and potassium concentration.	thermoplasma acidophilum is a free-living thermophilic mycoplasma. although the organism lacks a cell wall, it can grow in medium as dilute as 66 mosm. the intracellular k+ concentration can be as low as 17 mm, but varies according to the osmolality of the culture medium. the internal ph can be measured by taking advantage of the fact that t. acidophilum undergoes lysis when the ph is adjusted to neutrality. thus, by appropriate analysis of titration curves, it is possible to conclude that the i ...	1976	12804
membrane potential of thermoplasma acidophila.		1977	14021
zeta-potential and surface charge of thermoplasma acidophila.	the surface charge density and the zeta-potential of thermoplasma acidophila was estimated from microscopic electrophoresis experiments. the cells moved towards the positive electrode. the mobility remained constant from ph 2 to 5, and increased for ph values higher than 6. the mobility at ph 6 decreased dramatically with increased external ca2+ concentration. at ph 2 and an ionic strength similar to that of the growth medium, the zeta-potential was about 8 mv, negative relative to the bulk medi ...	1977	18171
ultrastructure of lipopolysaccharide isolated from thermoplasma acidophilum.	the fine structure of lipopolysaccharide isolated from thermoplasma acidophilum was examined by electron microscopy. negative staining of the lipopolysaccharide revealed long, ribbon-like structures with some branching. the average width of the lipopolysaccharide ribbons was 5 nm. treatment of the lipopolysaccharide with 0.5% sodium dodecyl sulfate resulted in the dissociation of the ribbon-like structures to spherical- and vesicular-shaped particles and some short, rodlike structures. results s ...	1975	46226
physiology of thermophilic bacteria.		1979	95242
the effect of a13+ on the physical properties of membrane lipids in thermoplasma acidophilum.		1978	215137
structure of membrane lipids and physico-biochemical properties of the plasma membrane from thermoplasma acidophilum, adapted to growth at 37 degrees c.	thermoplasma acidophilum, a mycoplasma-like organism, grows optimally at 56 degrees c and ph2. the low temperature extreme of growth is 37 degrees c. the plasma membrane of cells grown at 37 degrees c was isolated and characterized physicobiochemically. membrane lipids which comprise 25% of the membrane dry weight consist mainly of two repetitively methyl-branched c40 side chains that were ether-linked to two glycerol molecules. the lipid structures were elucidated by combined gas chromatography ...	1979	221032
membrane properties of thermoplasma acidophila.	plasma membranes were isolated from thermoplasma acidophila, a mycoplasma-like organism which grows optimally at ph 2 and 59 degrees. cells in concentrated suspensions were lysed by titrating to ph 9.3. the membranes were purified by washing at ph 10 and centrifuging in a discontinuous sucrose gradient. membrane purity was assessed by electron microscopy, determination of deoxyribonucleic acid content, polyacrylamide gel electrophoretic behavior. gel patterns and amino acid composition of cells ...	1975	234745
intracellular ph of thermoplasma acidophila.	thermoplasma acidophila, a mycoplasma-like organism, was grown at 56 degrees c and ph 2. the intracellular ph of this organism is close to neutral as measured by the distribution of a radioactive weak organic acid, 5,5-dimethyl-2,4-oxazolidinedione, across the plasma membrane. the cell can maintain the ph gradient when subjected to heat or to metabolic inhibitors. our experiments seem to indicate that a major portion of the ph gradient is not maintained by active processes, but rather by a donna ...	1975	236035
histone-like protein in the prokaryote thermoplasma acidophilum.	the dna of the prokaryote thermoplasma acidophilum is associated with a histone-like protein that has the following properties: it has a high content (23%) of basic amino acids, is positively charged at neutral ph, is soluble in acid, and can stabilize dna against thermal denaturation. in polyacrylamide gel electrophoresis, in the presence of either sodium dodecylsulfate or urea, it migrates at the same rate as histone iv (f2a1) of calf thymus. the amino acid composition, however, it unusually r ...	1975	238622
lipoquinones of some bacteria and mycoplasmas, with considerations on their functional significance.	in a comparative study the lipoquinones of some chemoorganotrophic, facultatively aerobic bacteria, and representative acholeplasma, mycoplasma, spiroplasma, and thermoplasma strains were investigated. the quinones were partly purified by preparative thin layer chromatography of lipid extracts, and characterized by their difference spectra (reduced minus oxidized) and rf values. respiring bacteria expectedly contained benzoquinones and/or naphthoquinones in micromolar concentrations whereas some ...	1977	413478
squalenes, phytanes and other isoprenoids as major neutral lipids of methanogenic and thermoacidophilic "archaebacteria".	the neutral lipids of nine species of methanogenic bacteria including five methanobacilli, two methanococci, a methanospirillum, one methanosarcina as well as two thermoacidophilic bacteria, thermoplasma and sulfolobus, were analyzed. the major components were c30, c25 and/or c20 acylic isoprenoid hydrocarbons with a continuous range of hydroisoprenoid homologues. the range of acyclic isoprenoids detected were from c14 to c30. apart from methanosarcina barkeri, squalene and/or hydrosqualene deri ...	1979	458874
purification and partial characterization of a procaryotic glycoprotein from the plasma membrane of thermoplasma acidophilum.	the obligate, thermophilic, acidophilic mycoplasma, thermoplasma acidophilum, grows optimally at 56 degrees c and ph 2.0. its plasma membrane possessed 21--22 protein bands that were resolved by polyacrylamide gel electrophoresis. one major membrane protein, molecular weight 152 000, which stained for carbohydrate with periodic acid-schiff reagent, accounted for 32% (w/w) of the total membrane proteins. it was isolated and further purified by concanavalin a affinity chromatography. the carbohydr ...	1979	534627
the evolution of histones in relationship to recent advances in elucidating chromatin structure.		1979	555823
ultrastructural localization of thermoplasma acidophilum surface carbohydrate by using concanavalin a.	surface carbohydrate, presumably the lipopolysaccharide, of thermoplasma acidophilum was visualized by means of the concanavalin a, horseradish peroxidase, and diaminobenzidine cytochemical staining procedure.	1978	641014
phylogenetic affinities between eukaryotic cells and a thermophilic mycoplasma.	thermoplasma acidophilum, a thermophilic mycoplasma, has several unusual features suggesting a possible relationship to eukaryotic cells. one feature is a histone-like protein that is associated with the dna, condensing it into subunits similar to those in eukaryotic chromatin. a second feature is an association of cytoplasmic proteins that resembles eukaryotic actin and myosin. these two components are widely distributed in different groups of eukaryotic cells, but are typically lacking in prok ...	1978	656568
a restriction enzyme tha i from the thermophilic mycoplasma thermoplasma acidophilum.	a type ii restriction enzyme (tha i) has been isolated from the thermophilic mycoplasma thermoplasma acidophilum. a new method of general application was used to determine the dna sequence cleaved by the enzyme. tha i cuts dna in the centre of the sequence cgcg. single-stranded dna is not a substrate. tha i does not cut t. acidophilum dna which is presumably modified. this is the first description of a restriction enzyme from a mycoplasma. because tha i is easily prepared in large amounts of app ...	1978	673834
physiologically important stabilization of dna by a prokaryotic histone-like protein.	the thermophilic mycoplasma thermoplasma acidophilum has tightly bound to its dna a protein that closely resembles the histones of eukaryotes. dna associated with this protein is more stable than free dna against thermal denaturation by about 40 degrees c, as shown in both native nucleoprotein and in hybrid nucleoprotein reconstituted in vitro with calf dna. since only about 20 percent of the dna in this organism is associated with the histone-like protein, we suggest that its physiological func ...	1978	694528
diphytanyl and dibiphytanyl glycerol ether lipids of methanogenic archaebacteria.	the lipids of nine different methanogenic bacterial strains are comprised of diphytanyl glycerol diethers, previously known only in extremely halophilic bacterial, as well as dibiphytanyl diglycerol tetraethers, known formerly only in the extremely thermoacidophilic bacteria thermoplasma and sulfolobus. of the methanogens examined from four representative taxonomic groups, methanobacterium and methanospirillum contained both types of isopranyl ethers in nearly equal proportions, whereas the cocc ...	1979	758677
flagellation and swimming motility of thermoplasma acidophilum.	electron microscopy of thin sections of thermoplasma acidophilum confirmed previous observations of the absence of a typical cell wall in this organism. negatively stained specimens revealed the almost consistent occurrence in both strains examined of monotrichously arranged flagella, about 9 micrometer long, which describe a sinuous curve with a wavelength of 1.5 to 2.0 micrometer and an amplitude of 0.33 to 0.59 micrometer. motility of t. acidophilum could be demonstrated microscopically by mi ...	1979	762021
long-chain diglycerol tetraethers from thermoplasma acidophilum.	the c40 isopranol-containing glycerol ether residues which characterize the complex lipids of the extreme thermoacidophile thermoplasma acidophilum were isolated and purified from the glycolipid and phospholipid fractions. the glycerol ether, as well as the acetate and methoxy derivatives were characterized by thin-layer, gel-permeation and gas-liquid chromatography, infrared, nuclear magnetic resonance and mass spectrometry and by vapor phase osmometry. the glycerol ethers are proposed to be un ...	1977	857900
polypeptide nature of growth requirement in yeast extract for thermoplasma acidophilum.	the active component(s) in yeast extract required by thermoplasma acidophilum for growth is polypeptide in nature. a fraction from yeast extract was isolated and partially characterized as one or more peptides of molecular weight about 1,000 containing 8 to 10 amino acids. although it was composed largely of basic and dicarboxylic amino acids, only one amino group per molecule was free. the polypeptide(s) appeared to bind avidly to cations. no other organic compounds except glucose were needed b ...	1975	1102535
distribution and composition of lipopolysaccharides from mycoplasmas.	polymeric carbohydrates containing glycerol and fatty acids were isolated from whole cells and membranes of mycoplasmas by hot aqueous phenol extraction and gel filtration. lipopolysaccharides were found to occur in four species of acholeplasma, two of anaeroplasma, and in mycoplasma neurolyticum. none were detected in spiroplasma citri or in five species of mycoplasma. all lipopolysaccharides contained both neutral and n-acylated amino sugars in ratios varying from 1:1 to 3:1. the neutral sugar ...	1976	1254559
localization of a sequence motif complementary to the nuclear localization signal in proteasomes from thermoplasma acidophilum by immunoelectron microscopy.	a sequence motif complementary to the nuclear localization signal (nls) has been localized in proteasomes from thermoplasma acidophilum by immunoelectron microscopy using sequence-specific antibodies. the antibodies were generated in two different ways: by immunization with a carrier-coupled peptide and by isolation of the sequence-specific antibody from an immune serum against native proteasomes using a peptide-affinity column. the sequence specificity of the isolated antibody was confirmed by ...	1992	1288618
purification and enzymic characterization of the cytoplasmic pyrophosphatase from the thermoacidophilic archaebacterium thermoplasma acidophilum.	cytoplasmic pyrophosphatase has been isolated from the thermoacidophilic archaebacterium thermoplasma acidophilum. the enzyme was purified to electrophoretic homogeneity by combining ion-exchange and affinity-chromatographic separations. this soluble pyrophosphatase probably consists of six identical subunits, since sds/page gave an estimate of about 22 kda for a single subunit and size-exclusion chromatography under non-denaturing conditions indicates a molecular mass of 110 +/- 5 kda. the two ...	1992	1327774
cloning and sequencing of the gene for the cytoplasmic inorganic pyrophosphatase from the thermoacidophilic archaebacterium thermoplasma acidophilum.	the gene (ppa) from the thermoacidophilic archaebacterium thermoplasma acidophilum, encoding the cytoplasmic pyrophosphatase, has been cloned. two degenerate oligonucleotide probes, synthesized according to the n-terminal amino acid sequence of the isolated protein, were used to screen subgenomic libraries. the dna-derived amino acid sequence of the archaebacterial enzyme allows, for the first time, comparative studies of cytoplasmic pyrophosphatases to be extended to all three urkingdoms. the a ...	1992	1327775
subunit stoichiometry and three-dimensional arrangement in proteasomes from thermoplasma acidophilum.	the proteasome or multicatalytic proteinase from the archaebacterium thermoplasma acidophilum is a 700 kda multisubunit protein complex. unlike proteasomes from eukaryotic cells which are composed of 10-20 different subunits, the thermoplasma proteasome is made of only two types of subunit, alpha and beta, which have molecular weights of 25.8 and 22.3 kda, respectively. in this communication we present a three-dimensional stoichiometric model of the archaebacterial proteasome deduced from electr ...	1992	1373380
biochemical properties of the proteasome from thermoplasma acidophilum.	we have purified proteasomes to apparent homogeneity from the archaebacterium thermoplasma acidophilum. this proteinase has a molecular mass of about 650 kda and an isoelectric point of 5.6. the proteasome hydrolyses peptide substrates containing an aromatic residue adjacent to the reporter group, as well as [14c]methylated casein optimally at ph 8.5 and 90 degrees c. the enzyme activity is enhanced severalfold by mg2+ and ca2+ at 25-500 mm. this increase in activity results primarily from a cha ...	1992	1396684
nucleotide sequence of the genes encoding the subunits h, b, a' and a'' of the dna-dependent rna polymerase and the initiator trna from thermoplasma acidophilum.		1992	1408839
black lipid membranes of tetraether lipids from thermoplasma acidophilum.	black lipid membranes were formed of tetraether lipids from thermoplasma acidophilum and compared to the bilayer forming lipids diphytanoylphosphatidylcholine and diphythanylglucosylglycerol. bilayer-forming lipids varied in thickness of black lipid membranes due to the organic solvent used. measurements of the specific membrane capacitance (cm = 0.744 microf/cm2) showed that the membrane-spanning tetraether lipids from thermoplasma acidophilum form a monolayer of a constant thickness of 2.5-3.0 ...	1992	1420295
production of an antiserum specific to the adp-ribosylated form of elongation factor 2 from archaebacteria and eukaryotes.	an antiserum to adp-ribosylated elongation factor 2 (adpr-ef-2) from s. acidocaldarius was raised in rabbits using stained, homogenized, adpr-ef-2-containing slices from sds-gels as a source of antigen. elongation factor 2 (ef-2) from s. acidocaldarius was cloned in e. coli and the expressed gene product was used in order to adsorb all anti-ef-2 antibodies which do not contain the adp-ribosyl group within their epitopes, as e. coli is unable to synthesize the adp-ribosyl acceptor diphthamide. th ...	1992	1426243
expression of functional thermoplasma acidophilum proteasomes in escherichia coli.	the two genes encoding the constituent subunits of the thermoplasma acidophilum proteasome were expressed in escherichia coli yielding fully assembled molecules as shown by electron microscopy. the recombinant proteasomes were purified to homogeneity and were shown to have proteolytic activity indistinguishable from proteasomes isolated from t. acidophilum.	1992	1426246
purification and properties of pyruvate kinase from thermoplasma acidophilum.	thermoplasma acidophilum is a thermoacidophilic archaebacterium occupying a paradoxical place in phylogenetic trees (phenotypically it is a thermoacidophile but phylogenetically it classifies with the methanogens). to better understand its phylogeny, the pyruvate kinase from this organism is being investigated as a molecular marker. the enzyme has been purified and has a native m(r) of 250,000. it consists of four, apparently identical subunits each of m(r) 60,000. no remarkable kinetic differen ...	1992	1426985
nucleotide sequence of the gene coding for ribosomal protein s10 from the archaeum thermoplasma acidophilum.		1992	1508693
conversion, by limited proteolysis, of an archaebacterial citrate synthase into essentially a citryl-coa hydrolase.	1. limited proteolysis of citrate synthase from sulfolobus solfataricus by trypsin reduced the rate of the overall reaction (acetyl-coa + oxaloacetate + h2o----citrate + coash) to 4% but did not affect the hydrolysis of citryl-coa. experimental results indicate that a connecting link between the enzyme's ligase and hydrolase activity becomes impaired specifically on treatment with trypsin. other proteolytic enzymes like chymotrypsin and subtilisin inactivated catalytic functions of citrate synth ...	1992	1521537
calorimetry of tetraether lipids from thermoplasma acidophilum: incorporation of alamethicin, melittin, valinomycin, and nonactin.	the development and application of model membrane systems on the basis of tetraether lipids from thermoplasma acidophilum has been proposed. in this respect incorporation of membrane proteins and ionophores is indispensable and is demonstrated in the case of alamethicin, melittin, nonactin, and valinomycin by calorimetry. dipalmitoylphosphatidylcholine (dppc) and dihexadecylmaltosylglycerol (dhmg) were chosen for comparison. melittin and alamethicin prove to broaden the lipid phase transition an ...	1992	1567197
transcription in vivo and in vitro of the histone-encoding gene hmfb from the hyperthermophilic archaeon methanothermus fervidus.	immediately upstream of the hmfb gene, in a dna fragment cloned from methanothermus fervidus, are two identical tandemly repeated copies of a 73-bp sequence that contain the sequence 5'tttatata, which conforms precisely to the consensus tata box element proposed for methanogen promoters. by using this duplicated region as the template dna and a cell-free transcription system derived from methanococcus thermolithotrophicus, transcription in vitro was found to initiate at two identical sites 73 bp ...	1992	1592806
early evolutionary relationships among known life forms inferred from elongation factor ef-2/ef-g sequences: phylogenetic coherence and structure of the archaeal domain.	phylogenies were inferred from both the gene and the protein sequences of the translational elongation factor termed ef-2 (for archaea and eukarya) and ef-g (for bacteria). all treeing methods used (distance-matrix, maximum likelihood, and parsimony), including evolutionary parsimony, support the archaeal tree and disprove the "eocyte tree" (i.e., the polyphyly and paraphyly of the archaea). distance-matrix trees derived from both the amino acid and the dna sequence alignments (first and second ...	1992	1602493
the pyruvate kinase of thermoplasma acidophilum: purification, kinetic characterisation & use as a phylogenetic marker.		1992	1633935
organization and expression of the 16s, 23s and 5s ribosomal rna genes from the archaebacterium thermoplasma acidophilum.	to elucidate the organization of the transcription units encoding the 16s, 23s and 5s rrnas in the archaebacterium thermoplasma acidophilum, the nucleotide sequences flanking the three rrna genes were determined, and the 5' and 3' termini of the rrna transcripts were mapped by primer extension and nuclease s1 protection. the results show that each of the rrnas is transcribed separately, consistent with the lack of physical proximity among them in the t. acidophilum genome. the transcription init ...	1990	1697064
posttranscriptional modification of trna in thermophilic archaea (archaebacteria).	nucleoside modification has been studied in unfractionated trna from 11 thermophilic archaea (archaebacteria), including phylogenetically diverse representatives of thermophilic methanogens and sulfur-metabolizing hyperthermophiles which grow optimally in the temperature range of 56 (thermoplasma acidophilum) to 105 degrees c (pyrodictium occultum), and for comparison from the most thermophilic bacterium (eubacterium) known, thermotoga maritima (80 degrees c). nine nucleosides are found to be un ...	1991	1708763
primary structure of the thermoplasma proteasome and its implications for the structure, function, and evolution of the multicatalytic proteinase.	the proteasome or multicatalytic proteinase is a high molecular mass multisubunit complex ubiquitous in eukaryotes but also found in the archaebacterial proteasome is made of two different subunits only, and yet the complexes are almost identical in size and shape. cloning and sequencing the gene encoding the small (beta) subunit of the t. acidophilum complex completes the primary structure of the archaebacterial proteasome. the similarity of the derived amino acid sequences of 233 (alpha) and 2 ...	1992	1734972
the multicatalytic proteinase (prosome, proteasome): comparison of the eukaryotic and archaebacterial enzyme.	proteasomes isolated and purified from rat muscle tissue and from the archaebacterium thermoplasma acidophilum have a very similar size and shape, but the subunit composition is less complex in the archaebacterium as compared to the eukaryotic particle. the archaebacterial enzyme contains a catalytic site with chymotryptic specificity, which is inhibited by serine proteinase inhibitors and clearly differs from the eukaryotic particle which has a minimum of three catalytic sites for peptide bond ...	1991	1801710
one-step purification of bacterial lipid macroamphiphiles by hydrophobic interaction chromatography.	bacterial lipid macroamphiphiles extracted with phenol/water can be purified in one step by hydrophobic interaction chromatography. lipids and the major part of protein are separated from macroamphiphiles during phenol/water extraction. coextracted nucleic acids, polysaccharides, and residual protein are effectively removed by column chromatography on octyl-sepharose whereby macroamphiphiles are primarily adsorbed and later eluted with a buffered propanol gradient. the procedure is applicable to ...	1991	1862938
characterization of a quinole-oxidase activity in crude extracts of thermoplasma acidophilum and isolation of an 18-kda cytochrome.	a quinol-oxidase activity was detected in crude extracts of the thermoacidophilic archaebacterium thermoplasma acidophilum. the activity was optimal at ph 5.4 and 50 degrees c. the km for ubiquinol-10 was 18 microm. the enzyme was inhibited by 2n-heptyl-4-hydroxyquinoline n-oxide with a ki of 150 nm. ubiquinols with different side-chain lengths were oxidized at similar rates, whereas menaquinols were converted at 6-12-fold higher rates compared to ubiquinols. membranes from t. acidophilum contai ...	1991	1879426
thermotropic properties of dispersions of cholesterol with tetraether lipids from thermoplasma acidophilum.	the main glycophospholipid from thermoplasma acidophilum is composed of a diisopranol-2,3-glycerotetraether. the fraction of pentane cyclizations of its hydrocarbon chains increases with the growth temperature of the source organism (39-59 degrees c). hydrated mixtures of these lipids together with cholesterol have been studied by calorimetry. with the reduction of the phase transition temperatures and enthalpy changes of the transitions, cholesterol is readily incorporated into lipid monolayers ...	1991	1898093
localization of subunits in proteasomes from thermoplasma acidophilum by immunoelectron microscopy.	the subunit topography of the thermoplasma acidophilum proteasome was determined by immunoelectron microscopy using monospecific antibodies directed against the two constituent subunits (alpha,beta). anti-alpha-subunit igg was found to bind to the outer disks of the cylinder- or barrel-shaped molecule, while the binding sites of the anti-beta-subunit igg were mapped on the two inner rings. probably the homologues of the two subunits in the compositionally more complex but isomorphous eukaryotic ...	1991	1915873
purification and characterisation of an archaebacterial succinate dehydrogenase complex from the plasma membrane of the thermoacidophile sulfolobus acidocaldarius.	a succinate dehydrogenase complex was isolated in a three-step purification from plasma membranes of the thermoacidophilic archaebacterium sulfolobus acidocaldarius. it consists of four subunits: a, 66 kda; b, 31 kda; c, 28 kda and d, 12.8 kda. in the 141-kda native protein, the four subunits are present in an equimolar stoichiometry. the complex contains acid-non-extractable flavin, iron and acid-labile sulphide. maximal succinate dehydrogenase activities were recorded at ph 6.5, which coincide ...	1991	1935955
crystallization and preliminary crystallographic study of glucose dehydrogenase from the archaebacterium thermoplasma acidophilum.	single crystals of glucose dehydrogenase from the archaebacterium thermoplasma acidophilum were obtained using the hanging-drop vapour diffusion method and polyethylene glycol as a precipitant in the presence of nadp+ at ph 5.4. the crystals belong to the hexagonal space group p6122 or p6522, with unit cell dimensions a = b = 121.9 angstrom, c = 229.6 angstrom and with two molecules in the asymmetric unit.	1991	1960718
cloning and sequencing of the gene encoding the large (alpha-) subunit of the proteasome from thermoplasma acidophilum.	the gene encoding the alpha-subunit of the proteasome from the archaebacterium thermoplasma acidophilum was cloned and sequenced. the gene encodes for a polypeptide with 233 amino acid residues and a calculated molecular weight of 25870. sequence similarity of the alpha-subunit with the saccharomyces cerevisiae wild-type suppressor gene scll+ encoded polypeptide, which is probably identical with the subunit yc7-alpha of the yeast proteasome, lends support to a putative role of proteasomes in the ...	1991	1991516
expression and purification of plasmid-encoded thermoplasma acidophilum citrate synthase from escherichia coli.	the citrate synthase gene from the thermophilic archaebacterium thermoplasma acidophilum was expressed in escherichia coli, yielding an active product of the expected molecular weight. manipulation of the citrate synthase gene in a series of puc19 constructs showed that the presumed thermoplasma ribosome binding site is recognized by the e. coli ribosome. a rapid purification of the expression product to homogeneity was achieved, based on the thermostability of thermoplasma citrate synthase.	1991	2026248
the three-dimensional structure of proteasomes from thermoplasma acidophilum as determined by electron microscopy using random conical tilting.	the three-dimensional structure of proteasomes from the archaebacterium thermoplasma acidophilum has been determined to a resolution of approximately 2 nm from electron micrographs of negatively stained preparations using the method of 'random conical tilting'. the particles turn out to be essentially cylinder-shaped barrels, 15 nm long and 11 nm wide, enclosing a tripartite inner compartiment. an account is given of some of the present limitations which prevent to attain a higher resolution and ...	1991	2037064
cloning and sequencing of the fus-gene encoding elongation factor 2 in the archaebacterium thermoplasma acidophilum.	we have cloned a 1.6-kb region of chromosomal dna from thermoplasma acidophilum into escherichia coli using as a probe part of the methanococcus vannielii fus-gene. the sequence of the clone was highly homologous to part of the corresponding methanococcus vannielii gene. by chromosome walking, a 4.7-kb ecori fragment containing the complete gene was isolated. nucleotide sequencing revealed an open reading frame of 2196 nucleotides. the deduced amino acid sequence contains the known peptide seque ...	1991	2044939
incorporation of synthetic peptide helices in membranes of tetraether lipids from thermoplasma acidophilum. a calorimetric study.	four analogues of the membrane-modifying, alpha-helical polypeptide antibiotic alamethicin were synthesized. the alpha-helical deca-, undeca-, heptadeca-, and icosapeptides were mixed with the main tetraether lipid of the archaebacterium thermoplasma acidophilum (mpl), dipalmitoylphosphatidylcholine (dppc) and dihexadecylmaltosylglycerol (dhmg) in various ratios and the modification of the lipid phase transition was determined by differential thermal analysis (dta). the polypeptides form mixed p ...	1991	2059650
small ribosomal subunit rna sequences, evolutionary relationships among different life forms, and mitochondrial origins.	a tree was constructed from a structurally conserved area in an alignment of 83 small ribosomal subunit sequences of eukaryotic, archaebacterial, eubacterial, plastidial, and mitochondrial origin. the algorithm involved computation and optimization of a dissimilarity matrix. according to the tree, only plant mitochondria belong to the eubacterial primary kingdom, whereas animal, fungal, algal, and ciliate mitochondria branch off from an internal node situated between the tree primary kingdoms. t ...	1990	2111858
purification and characterization of a dna polymerase from the archaebacterium thermoplasma acidophilum.	a thermophilic dna polymerase has been purified to near homogeneity from the archaebacterium thermoplasma acidophilum. analysis of the purified enzyme by sodium dodecyl sulfate gel electrophoresis revealed a single polypeptide of 88 kda which co-sediments with the dna polymerase activity on sucrose gradients. combination of sedimentation and gel filtration analyses indicates that this dna polymerase is an 88-kda monomeric enzyme in its native form. the dna polymerase is resistant to aphidicolin, ...	1990	2115439
[the archaebacterial ribosome].		1990	2181533
the primary structure of dna binding protein ii from the extreme thermophilic bacterium thermus thermophilus.	the primary structure of dna binding protein ii (dna bp ii) from the extreme thermophilic bacterium thermus thermophilus has been established by combination of manual and automated techniques. the protein has 95 residues and a molecular mass of 11,843. comparison of the primary structure with the known sequence data of dna bp ii from clostridium pasteurineum, baccillus stearothermophilus, escherichia coli, rhizobium meliloti, anabena, thermoplasma acidophilum, pseudomonas aeruginosa and bacillus ...	1990	2226865
citrate synthase from the thermophilic archaebacterium thermoplasma acidophilium. cloning and sequencing of the gene.	the gene encoding the citric acid cycle enzyme, citrate synthase, has been cloned from the thermoacidophilic archaebacterium, thermoplasma acidophilum. we report the sequencing of this gene and its flanking regions, and the derived amino acid sequence of the enzyme is compared by multiple-sequence alignment analysis with those of citrate synthases from eubacterial and eukaryotic organisms. the similarity is less than 30% between the archaebacterial and non-archaebacterial sequences, although the ...	1990	2269303
cloning and sequencing of the gene coding for the elongation factor 1 alpha from the archaebacterium thermoplasma acidophilum.	the gene which encodes the elongation factor 1 alpha (ef-1 alpha) of the archaebacterium thermoplasma acidophilum (tuf-gene) has been cloned and sequenced. the gene coding for elongation factor ef-2 was found downstream from the 3' end of the tuf-gene. comparison of the predicted amino acid sequence of thermoplasma ef-1 alpha with ef-1 alpha sequences of other organisms showed that the highest similarity values were found between t. acidophilum and methanococcus vannielii.	1990	2272495
physicochemical characterization of tetraether lipids from thermoplasma acidophilum. v. evidence for the existence of a metastable state in lipids with acyclic hydrocarbon chains.	the main glycophospholipid of thermoplasma acidophilum, grown at 39 degrees c, is composed of a di-isopranol-2,3-glycerotetraether. it has been characterized in hydrated systems by calorimetry. unlike its equivalent grown at 59 degrees c, it shows complex phase properties, which include at least three different phases, (1) a liquid-analogue state (c), which is stable above 20 degrees c, (2) a metastable solid-analogue state (a) formed by supercooling of the liquid-analogue state (c) and (3) a st ...	1990	2337621
improved procedure for the isolation of a double-strand-specific ribonuclease and its application to structural analysis of various 5s rrnas and trnas.	an improved method for the isolation of a double-strand-specific rnase from snake venom is presented. this rnase, called csv, was used to cleave yeast trnaphe and trna2glu and trnafmet from escherichia coli. in addition these rnas and e. coli trnaphe were examined with the single-strand-specific nuclease s1. the results are discussed in terms of the specificity of csv rnase and the structure of trnas. s1 nuclease digestions at increasing temperatures allowed the melting of tertiary and secondary ...	1986	2417836
aminoglycoside-induced mistranslation in thermophilic archaebacteria.	the effect of selected aminoglycoside antibiotics on the translational accuracy of poly(u) programmed ribosomes derived from the thermophilic archaebacteria thermoplasma acidophilum, sulfolobus solfataricus, thermococcus celer and desulfurococcus mobilis has been determined. under optimum temperature and ionic conditions for polyphenylalanine synthesis, the four species investigated are found to be markedly diverse in their response to the miscoding-inducing action of aminoglycoside antibiotics. ...	1988	2465484
the structure and organization of the 16s ribosomal rna gene from the archaebacterium thermoplasma acidophilum.	the complete nucleotide sequence of the 16s rrna gene from thermoplasma acidophilum, as well as its 5' and 3' flanking regions, were determined by the dideoxynucleotide chain termination method. the 16s rrna gene encodes 1471 nucleotides. the primary and secondary structures of t. acidophilum 16s rrna both exhibit typical archaebacterial features. the sequence appears to be more closely related to 16s rrnas of the methanogen--halophile group than to those of the thermoacidophile group. secondary ...	1989	2470478
phylogenetic conservation of antigenic determinants in archaebacterial elongation factors (tu proteins).	by using affinity chromatography methods, we have purified elongation factor tu (ef-tu) proteins from a host of archaebacteria covering all known divisions in the archaebacterial tree except halophiles, and from such distantly related eubacteria as thermotoga maritima and escherichia coli. polyclonal antibodies were raised against the tu proteins of sulfolobus solfataricus, thermoproteus tenax, thermococcus celer, pyrococcus wosei, archaeoglobus fulgidus, methanococcus thermolitotrophicus, therm ...	1989	2470483
the structure and evolution of archaebacterial ribosomal rnas.	a cladistic analysis of 553 5s rrna sequences has revealed a ur-5s rrna, the ancestor of all present-day 5s rrna molecules. previously stated characteristic differences between the eubacterial and eukaryotic molecules, namely, the length base-pairing schemes of helices d, can be used as a marker for the various archaebacterial branches. one model comprises thermococcus, thermoplasma, methanobacteria, and halobacteria; a second comprises the sulfolobales; and a third is represented only by the si ...	1989	2470487
archaebacteria: their phylogenetic relationship with the eubacterial and eukaryotic kingdoms.	in microbiology the discovery of archaebacteria ten years ago has wrought a profound change in the concepts of physiology, taxonomy, ecology, biochemistry, molecular biology, genetics and phylogeny. this review offers a concise summary of the state of the art in this field with special reference to taxonomy and ecology as well as to the different methodologies used to study the phylogeny of this unusual group of microorganisms that question many well established biological concepts.	1988	2481476
comparison of initiating abilities of primers of different length in polymerization reactions catalyzed by dna polymerases from thermoacidophilic archaebacteria.	optimal conditions for polymerization reaction catalyzed on poly(da) and poly(dt) templates by dna polymerases from thermoacidophilic archaebacteria--dna polymerase a from sulfolobus acidocaldarius and dna polymerase b from thermoplasma acidophilum--have been established. values of km and vmax (60 degrees c) for a set of primers d(pa)n and d(pt)n have been estimated. minimal primers for both enzymes are dnmp. lengthening of primers by each mononucleotide increases their affinity about 2.16-fold. ...	1989	2497779
the multicatalytic proteinase (prosome) is ubiquitous from eukaryotes to archaebacteria.	from the thermoacidophilic archaebacterium, thermoplasma acidophilum, a proteolytically active particle has been isolated which is almost identical in size and shape with the multicatalytic proteinase (prosome) from rat. this result indicates that prosomes have been developed early in evolution and that they possibly serve functions common to all living cells.	1989	2502434
preliminary x-ray crystallographic study of malate dehydrogenases from the thermoacidophilic archaebacteria thermoplasma acidophilum and sulfolobus acidocaldarius.	malate dehydrogenases from the thermoacidophilic archaebacteria thermoplasma acidophilum and sulfolobus acidocaldarius have been crystallized and characterized by x-ray diffraction measurements. crystals of the enzyme from t. acidophilum display space-group symmetry p2(1), a = 63 a, b = 135 a, c = 83 a and beta = 105 degrees; they scattered to approximately 4 a resolution. two crystal modifications of malate dehydrogenase from s. acidocaldarius were characterized; one displayed trigonal symmetry ...	1989	2507788
phenotypic characterization of the archaebacterial genus sulfolobus: comparison of five wild-type strains.	though amenable to routine manipulation and a popular subject of molecular genetic and biochemical studies on archaebacteria, the genus sulfolobus has remained poorly described in phenotypic terms. to delineate their physiological capabilities and diversity, five laboratory strains, including type strains of the described species sulfolobus acidocaldarius and s. solfataricus, were compared with respect to a variety of growth and biochemical parameters, including component profile of the surface- ...	1989	2512283
phenylalanine-to-tyrosine singlet energy transfer in the archaebacterial histone-like protein hta.	the archaebacterium thermoplasma acidophilum has a histone-like protein (hta) abundantly associated with its deoxyribonucleic acid. each native tetrameric complex of hta contains 20 phenylalanine residues, 4 tyrosine residues, and no tryptophan. when the protein was excited by radiation at 252 nm, which is a wavelength absorbed predominantly by phenylalanine, the fluorescent emission was mostly from tyrosine. according to the excitation spectrum for this tyrosine fluorescence, the cause was ener ...	1989	2513885
studies on dna polymerases and topoisomerases in archaebacteria.	we have isolated dna polymerases and topoisomerases from two thermoacidophilic archaebacteria: sulfolobus acidocaldarius and thermoplasma acidophilum. the dna polymerases are composed of a single polypeptide with molecular masses of 100 and 85 kda, respectively. antibodies against sulfolobus dna polymerase did not cross react with thermoplasma dna polymerase. whereas the major dna topoisomerase activity in s. acidocaldarius is an atp-dependent type i dna topoisomerase with a reverse gyrase activ ...	1989	2541877
purification and characterization of glucose dehydrogenase from the thermoacidophilic archaebacterium thermoplasma acidophilum.	glucose dehydrogenase was purified to homogeneity from the thermoacidophilic archaebacterium thermoplasma acidophilum. the enzyme is a tetramer of polypeptide chain mr 38,000 +/- 3000, it is catalytically active with both nad+ and nadp+ cofactors, and it is thermostable and remarkably resistant to a variety of organic solvents. the amino acid composition was determined and compared with those of the glucose dehydrogenases from the archaebacterium sulfolobus solfataricus and the eubacteria bacill ...	1989	2803257
generation of a large, protonophore-sensitive proton motive force and ph difference in the acidophilic bacteria thermoplasma acidophilum and bacillus acidocaldarius.	the mechanism by which acidophilic bacteria generate and maintain their cytoplasmic ph close to neutrality was investigated. for this purpose we determined the components of proton motive force in the eubacterium bacillus acidocaldarius and the archaebacterium thermoplasma acidophilum. after correction for probe binding, the proton motive force of untreated cells was 190 to 240 mv between external ph 2 and 4. anoxia diminished total proton motive force and the transmembrane ph difference by 60 t ...	1985	2981803
archaebacterial malate dehydrogenases. the enzymes from the thermoacidophilic organisms sulfolobus acidocaldarius and thermoplasma acidophilum show a-side stereospecificity for nad+.	the stereoselective transfer of hydrogen from nadh to oxaloacetate catalysed by malate dehydrogenases (ec 1.1.1.37) from the thermoacidophilic archaebacteria sulfolobus acidocaldarius and thermoplasma acidophilum was studied by the p.m.r. method described by zhou & wong [(1981) j. biochem. biophys. methods 4, 329-338]. both enzymes are a-side (pro-r) stereospecific for nadh.	1985	2985051
[prospects for using thermoacidophilic bacteria in biotechnology].		1986	3078176
differential features of ribosomes and of poly(u)-programmed cell-free systems derived from sulphur-dependent archaebacterial species.	the properties of poly(u)-directed cell-free systems developed from the sulphur-dependent, thermophilic archaebacteria desulfurococcus mobilis, thermoproteus tenax, sulfolobus solfataricus, thermococcus celer and thermoplasma acidophilum have been compared. all systems are truly thermophilic in requiring incubation at temperatures close to the physiological optimum for cell growth. under optimized conditions the error frequency in trna selection is less than 0.4% at 80 degrees c, and synthetic e ...	1986	3087750
occurrence of coenzyme f420 and its gamma-monoglutamyl derivative in nonmethanogenic archaebacteria.	analysis of the fluorescent compounds extracted from six different species of halobacteria and one species each of sulfolobus and thermoplasma revealed the universal occurrence of coenzyme f420, (n-[n-[o-[5-(8-hydroxy-5-deazaisoalloxazin-10-yl)-2,3,4-trihydroxy -4-pentoxyhydroxyphosphinyl]-l-lactyl]-l-gamma-glutamyl]-l -glutamic acid), or its gamma-monoglutamyl derivative or both. the total amount (approximately 100 pmol/mg [dry weight]) of these compounds found in the halobacteria studied was a ...	1986	3093465
[biology of chemoautotrophs].		1988	3150584
membrane-bound atpase of a thermoacidophilic archaebacterium, sulfolobus acidocaldarius.	the membranes of sulfolobus, a thermoacidophilic archaebacterium showed two types of atp hydrolyzing activity. one was that of a neutral atpase at an optimum ph around 6.5. this enzyme was activated by 10 mm sulfate with a shift of optimum ph to 5. in these respects, the enzyme was similar to membrane-bound atpase of thermoplasma, another thermoacidophilic archaebacterium, reported by searcy and whatley [1982) zbl. bakt. hyg., i. abt. orig. c3, 245-257). the enzyme hydrolyzed atp and other ntps, ...	1985	3159431
5'-methylbenzimidazolyl-cobamides are the corrinoids from some sulfate-reducing and sulfur-metabolizing bacteria.	the sulfate-reducing bacteria desulfobacterium autotrophicum, desulfobulbus propionicus and archaeoglobus fulgidus (vc-16) and the sulfur-metabolizing archaebacteria desulfurolobus ambivalens and thermoplasma acidophilum were found to contain considerable amounts of corrinoids, that were isolated and crystallized in their co beta-cyano form. in three other sulfur-metabolizing archaebacteria, thermoproteus neutrophilus, pyrodictium occultum and staphylothermus marinus significant amounts of corri ...	1988	3416881
purification and properties of malate dehydrogenase from the thermoacidophilic archaebacterium thermoplasma acidophilum.	malate dehydrogenase from the thermoacidophilic archaebacterium thermoplasma acidophilum is purified 50-fold to electrophoretic homogeneity. the purified enzyme crystallizes readily. native malate dehydrogenase shows a relative molecular mass of 144 000. it is a tetramer of identical subunits with a relative molecular mass of 36 600. malate dehydrogenase from thermoplasma uses both nadh and nadph as coenzyme to reduce oxaloacetate. the enzyme shows a-side (pro-r) stereospecificity for both coenz ...	1986	3741624
glucose dehydrogenase from the thermoacidophilic archaebacterium sulfolobus solfataricus.	glucose dehydrogenase has been purified to homogeneity from cell extracts of the extreme thermoacidophilic archaebacterium sulfolobus solfataricus. the enzyme utilizes both nad+ and nadp+ as coenzyme and catalyses the oxidation of several monosaccharides to the corresponding glyconic acid. substrate specificity and oxidation rate depend on the coenzyme present; when nad+ is used, the enzyme binds and oxidizes specifically sugars presenting equatorial orientation of hydroxy groups at c-2, c-3 and ...	1986	3827812
[evolutionary status of acids-thermophilie archaebacteria].		1985	3906775
crystallization of a fe,zn superoxide dismutase from the archaebacterium thermoplasma acidophilium.	the novel fe,zn superoxide dismutase from the archaebacterium thermoplasma acidophilium has been crystallized in space groups p1, p2(1) and p2(1)2(1)2, with 2,4 and 1/2 of an 84,000 mr tetramer, respectively, estimated to be in the asymmetric unit of the unit cell. the orthorhombic crystals, which have unit cell dimensions a = 84.2 a, b = 72.7 a, c = 67.8 a, diffract x-rays to at least 2.0 a and are suitable for a determination of the three-dimensional structure of the fe,zn superoxide dismutase ...	1985	3935799
primary structure of elongation factor 2 around the site of adp-ribosylation is highly conserved from archaebacteria to eukaryotes.	elongation factor 2 (ef-2) from eukaryotes and archaebacteria can be adp-ribosylated by diphtheria toxin (dt) [(1977) annu. rev. biochem. 46, 69-94; (1980) nature 287, 250-251]. the primary structure of the adp-ribose accepting region in efs from the archaebacteria thermoplasma acidophilum halobacterium cutirubrum and methanococcus vannielli was determined in order to elucidate the degree of conservation compared with 4 previously established eukaryotic sequences [(1971) febs lett. 103, 253-255] ...	1985	3996598
preliminary x-ray diffraction studies on a ferredoxin from the thermophilic archaebacterium, thermoplasma acidophilum.	a ferredoxin from the thermophilic archaebacterium, thermoplasma acidophilum, is supposed to contain two (4fe-4s) active centers; one center could be linked by four cysteine residues to the protein and the other bonded with three cysteines and an unknown group. this ferredoxin has been crystallized by salting-out against 2.3 m-ammonium sulfate solution. the space group is p21212 with cell dimensions of a = 59.20 a, b = 52.77 a and c = 41.28 a. four molecules pack in the unit cell with vm = 2.03 ...	1985	4087301
immunodiffusion analysis of membranes of thermoplasma acidophilum.	isolates of thermoplasma acidophilum were divided into serological groups based on immunodiffusion studies of solubilized-membrane preparations.	1974	4210340
immunological analysis of glycolipids and lipopolysaccharides derived from various mycoplasmas.	the lipids and lipopolysaccharides of five mycoplasmas were examined for complement-fixing activity to antimembrane rabbit sera. total glycolipid fractions and the aqueous phenol fractions (lipopolysaccharides) from the membranes of acholeplasma laidlawii, a. modicum, a. axanthum, and mycoplasma neurolyticum exhibited significant antigenic activity. the glycolipids and phosphoglycolipids from thermoplasma acidophilum were either anticomplementary or did not react due to their extreme hydrophobic ...	1974	4215761
lipids of thermoplasma acidophilum.	cells of thermoplasma acidophilum contain about 3% total lipid on a dry weight basis. total lipid was found to contain 17.5% neutral lipid, 25.1% glycolipid, and 56.6% phospholipid by chromatography on silicic acid. the lipids contain almost no fatty acid ester groups but appear to have long-chain alkyl groups in ether linkages to glycerol. the phospholipid fraction includes a major component which represents about 80% of the lipid phosphorus and 46% of the total lipids. we believe this componen ...	1972	4344918
lipid phase transitions in membrane vesicles from thermoplasma acidophila.		1974	4370165
a new class of lipopolysaccharide from thermoplasma acidophilum.		1974	4371772
scanning electron microscopy of thermoplasma acidophilum.	the scanning electron microscope was utilized to observe the morphology of the thermophilic, acidophilic mycoplasma, thermoplasma acidophilum. upon examination of the surface morphology, the size and shape of this unusual mycoplasma revealed its similarity to the other mycoplasmas that have been investigated.	1974	4436262
characterization of the membranes of thermoplasma acidophilum.	thermoplasma acidophilum grows optimally under aeration at 59 c and ph 2. both intact cells and membranes disaggregate below ph 1 and above ph 5, producing no sedimentable particles. increase in ionic strength at ph 5 or below results in cellular lysis and membrane disaggregation. membranous components produced by lysis at alkaline ph reaggregate upon reduction of both ph and ionic strength. osmotic environment plays little role in cellular stability. membranes prepared by sonic lysis at ph 5 ex ...	1973	4583228
immunofluorescence approach to the study of the ecology of thermoplasma acidophilum in coal refuse material.	specific immunofluorescence staining was applied to the study of the localization, distribution, and growth of thermoplasma acidophilum in its natural habitat, the coal refuse pile. different antigenic groups of t. acidophilum could be isolated from the same refuse pile, and the same antigenic groups were isolated from piles from different geographical areas. no correlation could be established between the antigenic groups and the ph or temperature of the habitats. brightly fluorescing cells of ...	1974	4602306
a thermophilic, acidophilic mycoplasma isolated from a coal refuse pile.	a thermophilic, acidophilic procaryote lacking a cell wall has been isolated from a coal refuse pile which had undergone self-heating. electron micrographs, chemical assays for hexosamine, and the inability of vancomycin to inhibit growth confirm the lack of a cell wall. the apparent ability of the organism to reproduce by budding and the low guanine plus cytosine content of its dna indicate a relation to the mycoplasmas. the temperature optimum of the organism is 59 degrees c, and growth occurs ...	1970	5481857
taxonomic relations between archaebacteria including 6 novel genera examined by cross hybridization of dnas and 16s rrnas.	dnas from 16 species of archaebacteria including 6 novel isolates were hybridized with 16s rrnas from 7 species representing different orders or groups of the urkingdom of archaebacteria. the yields, normalized for the number of genes per microgram of dna, and the temperature stabilities of all hybrids were determined and related to each other. a taxonomic tree constructed from such fractional stability data reveals the same major divisions as that derived from comparative cataloging of 16s rrna ...	1982	6178834
genome organization and transcription in archaebacteria.	the genome organization of the archaebacteria is investigated in three model systems: a) rrna genes of various archaebacteria, b) a plasmid of 15.6 kb from sulfolobus acidocaldarius which exists in free or integrated form, c) the 59 kb genome of phage phi h of halobacterium halobium as a model for the unusual structural variability of dna in this organism. several variants of this phage have been isolated, their genomes differ by several insertions, a deletion, and an inversion. the frequent inv ...	1984	6202564
mycoplasma evolution: a review of the use of ribosomal and transfer rna nucleotide sequences in the determination of phylogenetic relationships.	comparison of the nucleotide sequences of "structural" rnas (ribosomal and transfer rna) has enabled the construction of phylogenetic trees to be achieved. data from 16s rrna, 5s rrna, and trna from a total of eight mollicutes (excluding t. acidophilum) including representatives of the families mycoplasmataceae, spiroplasmataceae, and acholeplasmataceae, show that these families share a close relationship and a common ancestor with the gram-positive eubacteria. thermoplasma acidophilum is a memb ...	1983	6206653