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aggregation-related conformational change of the membrane-associated coat protein of bacteriophage m13.the state of the coat protein of bacteriophage m13, reconstituted into amphiphilic media, has been investigated. the in situ conformation of the coat protein has been determined by using circular dichroism. minimum numbers for the protein aggregation in the system have been determined after disruption of the lipid-protein system and subsequent uptake of the protein in cholate micelles. the aggregational state and conformation of the protein were affected by (1) the method of coat protein isolati ...19892690954
initial steps in protein membrane insertion. bacteriophage m13 procoat protein binds to the membrane surface by electrostatic interaction.bacteriophage m13 procoat protein is synthesized on free polysomes prior to its assembly into the inner membrane of escherichia coli. as an initial step of the membrane insertion pathway, the precursor protein interacts with the cytoplasmic face of the inner membrane. we have used oligonucleotide-directed mutagenesis to study the regions of the procoat protein involved in membrane binding. we find that there is an absolute requirement for positively charged amino acids at both ends of the protei ...19902202592
effects of bacteriophage m13 infection upon phospholipid and fatty acid compositions of escherichia coli.escherichia coli k38 were grown and infected with wild type and amber mutants of bacteriophage m13 in the early log phase. lipid compositions of the infected and healthy cultures, grown under identical conditions, were determined 2 hr after infection. from the results, it was observed that total lipid and total phospholipid content remained nearly constant, suggesting that the cell membrane which contained the maximum phospholipids was not damaged by the infection. moreover, the percentage of di ...19751099382
[increase in stability of the recombinant phage m13 carrying escherichia coli genes rpijl by reducing expression of cloned genes].a recombinant phage mp9mw/rpob containing the bglii-b fragment of the escherichia coli rpljl-rpobc gene cluster was constructed on the basis of filamentous phage m13. stability of the phage was increased by insertion of a transcription terminator t beta' which blocked transcription of cloned genes from the plac of the vector.19902191898
studies on bacteriophage m13 dna. 2. the gene order of the m13 genome.the double-stranded replicative form dna of bacteriophage m13 was cleaved into 13 specific fragments by the restriction endonuclease from haemophilus aphirophilus. the individual dna fragments from wild-type replicative form molecules were then annealed to circular, single-stranded dnas of phage m13, bearing amber mutations as genetic markers. when such dna hybrids infected competent escherichia coli cells, only those duplexes which were genetically heterozygous gave rise to wild-type phages in ...19751095371
expression of bacteriophage m13 dna in vivo. i. synthesis of phage-specific rna and protein in minicells.it is demonstrated that after infection of the appropriate minicell-producing strain of escherichia coli with the filamentous bacteriophage m13, its replicative form dna is segregated into minicells. consequently these minicells have acquired the capability to direct the synthesis of phage-specific rna and protein. comparision of the electrophoretic mobilities of phage-specific rna species made in vitro with those made in m13 replicative form dna harbouring minicells, have indicated that almost ...1978363158
the function of a leader peptide in translocating charged amino acyl residues across a membrane.insertion of bacteriophage coat proteins into the membrane of infected bacterial cells can be studied as a model system of protein translocation across membranes. the coat protein of the filamentous bacteriophage pf3--which infects pseudomonas aeruginosa--is 44 amino acids in length and has the same basic structure as the coat protein of bacteriophage m13, which infects escherichia coli. however, unlike the pf3 coat protein, the m13 coat protein is synthesized as a precursor (procoat) with a typ ...19902124001
identification of potential active-site residues in the escherichia coli leader peptidase.leader peptidase of escherichia coli cleaves the leader sequence from the amino terminus of membrane and secreted proteins after these proteins insert across the membrane. despite considerable research, the mechanism of catalysis of leader peptidase remains unknown. this peptidase cannot be classified using protease inhibitors to the serine, cysteine, aspartic acid, or metallo- classes of proteases (zwizinski, c., date, t., and wickner, w. (1981) j. biol. chem. 256, 3593-3597). using site-direct ...19921618816
transmembrane region of wild-type and mutant m13 coat proteins. conformational role of beta-branched residues.although transmembrane (tm) segments of integral membrane proteins are putatively alpha-helical in conformation, beta-sheet promoters (val, ile, thr) often account for approximately 40% of tm residue composition. we are examining the conformational role(s) of these residues, using as a model system the major coat protein of the filamentous bacteriophage m13. this 50-residue protein, which is located at the escherichia coli host membrane during phage reproduction, contains a prototypic 19-residue ...19921544912
nucleotide sequence of gene vii and of a hypothetical gene (ix) in bacteriophage m13.a dna fragment containing gene vii of bacteriophage m13 has been transcribed and the nucleotide sequence of this 169-nucleotides long transcript was determined by rna sequencing methods. additionally, the nucleotide sequence of this gene and parts of its neighbouring genes v and viii has been determined by the dimethylsulphate-hydrazine technique. the reading frame of gene vii has been established by determining the nucleotide changes occurring in the transcripts of two amber mutants of this gen ...1978370777
backbone dynamics of a model membrane protein: 13c nmr spectroscopy of alanine methyl groups in detergent-solubilized m13 coat protein.the filamentous coliphage m13 possesses multiple copies of a 50-residue coat protein which is inserted into the inner membrane of escherichia coli during infection. 13c nuclear magnetic resonance (nmr) spectroscopy has been used to probe the structure and dynamics of m13 coat protein solubilized in detergent micelles. a comparison of backbone dynamics within the hydrophobic core region and the hydrophilic terminal domains was obtained by biosynthetic incorporation of [3-13c]alanine. alanine is d ...19863513830
mutant 16s ribosomal rna: a codon-specific translational suppressor.we have isolated an unusual codon-specific translational suppressor in escherichia coli. the suppressor resulted from a spontaneous mutation in a chromosomal gene during a selection for suppressors of the auxotrophic nonsense mutation trpa(uga211). the suppressor allows readthrough of uga mutations at two positions in trpa and at two sites in bacteriophage t4. it does not, however, suppress amber (uag) or ochre (uaa) mutations that were tested in both genomes, some of which were at the same posi ...19883288986
recombinant forms of m13 procoat with an ompa leader sequence or a large carboxy-terminal extension retain their independence of secy function.the assembly of phage m13 procoat protein into the plasma membrane of escherichia coli is independent of the secy protein. to test whether this is caused by the unusually small size of procoat, we fused dna encoding 103 amino acids to the carboxy-terminal end of the procoat gene. the resulting fusion protein, which attains the same membrane-spanning conformation as mature coat protein, still does not require the secy function for membrane assembly. to determine whether the leader sequence govern ...19873034592
solution hybridization of crosslinkable dna oligonucleotides to bacteriophage m13 dna. effect of secondary structure on hybridization kinetics and equilibria.several dna oligonucleotides have been photochemically modified with the furocoumarin 4'-hydroxymethyl-4,5',8-trimethylpsoralen (hmt) such that each contained a single hmt furan side monoadduct to thymidine at a unique 5' tpa 3' sequence. when these oligonucleotides were hybridized to their respective complements, the hmt adduct could be driven to form an interstrand crosslink by irradiation of the hybrid with 360 nm light. the ability to crosslink probe-target complexes has allowed us to determ ...19873316669
viable deletions of the m13 complementary strand origin.the single-stranded dna of bacteriophage m13 is converted to a duplex replicative form by a mechanism involving rna-primed initiation at a single unique site on the viral dna. the dna sequence that specifies the rna primer is contained largely within one of two adjacent hairpin structures protected from dnase degradation by rna polymerase. we have used in vitro techniques to construct a series of m13 mutants having deletions in the region of the complementary strand origin. deletions of the dupl ...19816273888
filamentous coliphage m13 as a cloning vehicle: insertion of a hindii fragment of the lac regulatory region in m13 replicative form in vitro.a hindii restriction fragment comprising the escherichia coli lac regulatory region and the genetic information for the alpha peptide of beta-galactosidase (beta-d-galactosidegalactohydrolase, ec. 3.2.1.23) has been inserted into 1 of the 10 bsu i cleavage sites of m13 by blunt end ligation. a stable hybrid phage was isolated and identified by its ability to complement the lac alpha function. further characterization of the hybrid phage includes retransformation studies, agarose gel electrophore ...1977333444
homologous recombination intermediates between two duplex dna catalysed by human cell extracts.using as substrates, 1: the replicative form (rf) of phage m13 mp8 in which the reading frame of the lac z' gene was disrupted by insertion of an octonucleotide, and 2: a restriction fragment one kb long, containing the functional lac z' gene (isolated from wild type m13 mp8), we show that nuclear extracts from human cells (3 lines tested) promote the targeted replacement of the altered sequence by the functional one. following incubation with the extracts, the dna's were introduced in jm 109 ba ...19873302944
[expression in escherichia coli of dna coding for human tumor necrosis factor].the variants of expression in escherichia coli of artificial dna coding for human tumor necrosis factor, an important immune modulator with selective cytotoxic action on a number of transformed cell lines have been described. the dna was placed under control of either phage m13 promoter of gene for main coat protein or tandem of pair of e. coli tryptophane promoters. it has been shown that e. coli cells harbouring plasmids described with artificial tnf gene provide good level of protein biosynth ...19883071369
folding of single-stranded dna on the histone octamer.a complex between the single-stranded dna of the bacteriophage m13 and the histone octamer was analyzed by electron microscopy, low-angle x-ray diffraction and nuclease analysis. the morphology and the diffraction pattern of the complex strongly resemble those of the nucleosome. these results, as well as the finding of a protected dna fragment about 100 nucleotides long following single-stranded dna specific nuclease digestion, indicate that 'a nucleosome-like' complex can be formed between sing ...19853882454
mutagenic specificity of alkylated and oxidized dna bases as determined by site-specific mutagenesis.this work demonstrates the use of the tools of site-specific mutagenesis to study the mutagenic activity of two dna adducts, o6-methylguanine and cis-thymine glycol. the former adduct is one of the methylated bases formed by carcinogenic and mutagenic alkylating agents. it was built into the single-stranded genome of bacteriophage m13 and replicated in escherichia coli (e. coli). the mutation frequency of o6-methylguanine was 0.4% in physiologically normal cells. in cells in which the repair sys ...19892665597
replication of uv-irradiated single-stranded dna by dna polymerase iii holoenzyme of escherichia coli: evidence for bypass of pyrimidine photodimers.replication of uv-irradiated circular single-stranded phage m13 dna by escherichia coli rna polymerase (ec 2.7.7.6) and dna polymerase iii holoenzyme (ec 2.7.7.7) in the presence of single-stranded dna binding protein yielded full-length as well as partially replicated products. a similar result was obtained with phage g4 dna primed with e. coli dna primase, and phage phi x174 dna primed with a synthetic oligonucleotide. the fraction of full-length dna was several orders of magnitude higher than ...19862941756
genes involved in transitory recombination between phage m13 and plasmid phv33.plasmid phv33 and phage m13 combine in escherichia coli cells to form a chimera, which decombines to regenerate two parental genomes. combination can occur via two genetic pathways, one defined by the recbc genes, the other by reca, recf and possibly recl genes. decombination can also occur via two pathways, one defined again by the recbc genes, the other by a gene not identified, but active only in the absence of the recl gene product.19846323172
replication of bacteriophage m13. x. m13 replication in a mutant of escherichia coli defective in the 5' leads to 3' exonuclease associated with dna polymerase i. 1976789894
novel eukaryotic expression vectors which permit single-stranded replication in escherichia coli and in vitro translational analysis of cloned genes.the ability to express cloned genes transiently is an important technique in the study of eukaryotic gene expression. numerous useful expression vectors have been constructed for this purpose although many of them share several common drawbacks. in this paper i describe the construction and characterization of novel expression vectors psvkii and psvkiii which have 13 and 8 unique restriction sites, respectively, suitable for cloning genes. these vectors have phage m13 ori, which permits them to ...19882850970
site-specific recombination at orit of plasmid r1162 in the absence of conjugative transfer.r1162 is efficiently comobilized during conjugative transfer of the self-transmissible plasmid r751. bacteriophage m13 derivatives that contain two directly repeated copies of orit, the site on r1162 dna required in cis for mobilization, were constructed. phage dna molecules underwent recombination during infection of escherichia coli, with the product retaining a single functional copy of orit. recombination was strand specific and depended on r1162 gene products involved in mobilization, but d ...19892644236
[identification and classification of strains of microorganisms using genomic fingerprinting with biotinylated phage m13 dna].to analyze dna polymorphisms of various bacterial strains, a nonradioactive variant of the genomic fingerprinting method was developed. the method was based on the application of biotin-labeled single-stranded phage m13 dna as a probe. characteristic patterns of fingerprints obtained by mvai, haeiii, and hinfi restriction enzymes are presented for several species of bacilli and other bacteria. the advantages of this method in microbiology for the identification and characterization of different ...19968964460
expression of bacteriophage m13 dna in vivo. isolation, identification and characterization of phage-specific mrna species. 19807007041
location of m13 coat protein in sodium dodecyl sulfate micelles as determined by nmr.the major coat protein (gviiip) of bacteriophage m13 solubilized in sodium dodecyl sulfate (sds) detergent micelles was used as a model system to study this protein in the lipid-bound form. in order to probe the position of gviiip relative to the sds micelles, stearate was added, spin-labeled at the 5- or 16-position with a doxyl group containing a stable nitroxide radical. the average position of the spin-labels in the micelles was derived from the line broadening of the resonances in the 13c s ...19947947703
expression of a dna strand initiation sequence of cole1 plasmid in a single-stranded dna phage.in order to investigate initiation of h-strand (lagging strand) replication of the plasmid cole1, the origin region fragment (hae ii-e) of cole1 was inserted into the intergenic region of filamentous dna phage m13 and cloned. a site capable of promoting dna strand initiation on a single-stranded dna template has been detected on the l-strand (leading strand) of the cloned fragment. the site, named rri-1 rifampicin-resistant initiation), directs conversion of chimeric phage single-stranded dna to ...19807005899
replication of m13 single-stranded dna bearing a site-specific ethenocytosine lesion by escherichia coil cell extracts.previous investigation on the mutagenic effects of 3, n4-ethenocytosine (epsilon c), a nonpairing dna lesion, revealed the existence of a novel sos-independent inducible mutagenic mechanism in e. coli termed uvm for uv modulation of mutagenesis. to investigate whether uvm is mediated by an alteration of dna replication, we have set up an in vitro replication system in which phage m13 viral single-stranded dna bearing a single site-specific (epsilon c) residue is replicated by soluble protein ext ...19979261557
differential use of the signal recognition particle translocase targeting pathway for inner membrane protein assembly in escherichia coli.assembly of several inner membrane proteins-leader peptidase (lep), a lep derivative (lep-inv) that inserts with an inverted topology compared with the wild-type protein, the phage m13 procoat protein, and a procoat derivative (h1-procoat) with the hydrophobic core of the signal peptide replaced by a stretch from the first transmembrane segment in lep-has been studied in vitro and in escherichia coli strains that are conditional for the expression of either the 54 homologue (ffh) or 4.5s rna, wh ...19989843943
inhibition of bacteriophage m13 replication with esterified milk proteins.esterified milk proteins [methylated (met) or ethylated (et) alpha-lactalbumin (ala), beta-lactoglobulin (blg), and beta-casein (bcn)], unmodified native milk proteins, and native basic proteins (calf thymus histone and hen egg white lysozyme) were tested for their antiviral activity against the bacteriophage m13 and for their influence on its replication (except bcn). all esterified milk proteins showed an antiviral activity against the bacteriophage m13, proportional to the extent of esterific ...200616719499
replication of the plasmid pbr322 under the control of a cloned replication origin from the single-stranded dna phage m13.the replication origins of viral and complementary strands of bacteriophage m13 dna are contained within a 507-nucleotide intergenic region of the viral genome. chimeric plasmids have been constructed by inserting restriction endonuclease fragments of the m13 intergenic region into the plasmid pbr322. replication of these hybrid plasmids, under conditions not permissive for the plasmid replicon, depends on specific segments of the m13 origin region and on the presence of m13 helper virus. thus m ...19806933512
replication of bacteriophage m13. xiv. differential inhibition of the replication of m13 and m13 miniphage in a mutant of escherichia coli defective in the 5' leads to 3' exonuclease associated with dna polymerase i.previous studies have shown that m13 single-strand synthesis is inhibited at nonpermissive temperature in escherichia coli polaexl, a temperature-sensitive mutant defective in the 5' leads to 3' exonuclease activity of polymerase i (t.-c. chen and d. s. ray, j. mol. biol. 106:589-604, 1976). under these conditions the formation of covalently closed replicative form (rf) molecules is greatly reduced, and miniature forms of rf accumulate. we show here that the accumulation of mini-rfs is the conse ...1978366176
from est to ihc: human antibody pipeline for target research.we have developed a method for the high-level expression of expressed sequence tags (ests) as inclusion bodies in escherichia coli by c-terminal fusion to the n1-domain of g3p of filamentous phage m13. soluble fusion protein is obtained by an efficient refolding procedure. we have applied such protein preparations to the selection of human antibody fragments from phage-displayed hucal libraries. for all fusion proteins tested in this study, hucal antibodies could be generated which specifically ...200312667684
evidence for two genetically distinct dna primase activities specified by plasmids of the b and i incompatibility groups.plasmid colib-p9 of the i alpha incompatibility group is known to encode a dna primase that acts in the conjugal transfer of the plasmid and can substitute for mutant dnag gene product in vegetative replication of the escherichia coli chromosome. the relevant genetic determinant (sog) has previously been cloned into a small multicopy vector plasmid. prototype incb plasmid r16 also suppresses host dnag mutations. the equivalent gene(s) (pri) of r16 was cloned into plasmid pbr325 and shown by filt ...19827045070
rapid mutational analysis of regulatory loci in escherichia coli k-12 using bacteriophage m13.a derivative of bacteriophage m13mp8 , designated m13mp8 /p, was prepared in which the promoter and nh2-terminal codons of bacterial genes may be fused to a portion of beta-galactosidase, resulting in an easily scorable phenotype. because transcription from the inserted promoter remains responsive to the host regulatory system, it is simple to screen mutagenized phage for isolates with aberrant regulatory phenotypes and to determine the mutational changes by dideoxy sequence analysis. the feasib ...19846427775
the use of bacteriophage m13 carrying defined fragments of the escherichia coli glta gene to determine the location and structure of the citrate synthase promoter region.the glta gene from escherichia coli, which encodes citrate synthase, has been located on a 3.24 kb hindiii/ecorl restriction fragment. this region contains one restriction site for bamhl and two for bglii. defined restriction fragments from this region were cloned into suitably cleaved replicative form m13mp8 and m13mp9. the recombinants (m13gtla1 leads to 10) were isolated as single stranded dna and characterised on the basis of molecular weight and dna sequence. the single stranded dna was con ...19836355771
characterization and properties of a modified human interferon-alpha containing an additional 18 amino acids at the n-terminus.a modified human interferon-alpha 2 was produced in escherichia coli cells infected with phage m13 mp7 containing an interferon-alpha gene. after purification by immunochromatography with the monoclonal antibody nk2, the n-terminal amino acid sequence was determined. the n-terminal methionine was absent but an additional sequence of 18 amino acids at the n-terminus was retained. the modified interferon-alpha 2 was indistinguishable from authentic interferon-alpha 2 in its ability to activate nat ...19836875519
comparison of specific binding sites for escherichia coli rna polymerase with naturally occurring hairpin regions in single-stranded dna of coliphage m13. 1978353054
mutability of bacteriophage m13 by ultraviolet light: role of pyrimidine dimers.the role of pyrimidine dimers in mutagenesis by ultraviolet light was examined by measuring the uv-induced reversion of six different bacteriophage m13 amber mutants for which the neighboring dna sequences are known. the mutational response at amber (tag) codons preceded by a guanine or adenine (where no pyrimidine dimer can be formed) were compared with those preceded by thymine or cytosine (where dimer formation is possible). equivalent levels of uv-induced mutagenesis were observed at both ki ...19827048024
loss of r factors promoted by bacteriophage m13 and the m13 carrier state.the infection of different hfr strains of escherichia coli bearing derepressed r factors of the fi(+) or fi(-) type can result in the loss of the r factor and the conversion of the infected cells to the r(-) state. this extends earlier observations on the elimination of f' factors by bacteriophage m13 infection. variability in the efficiency of this conversion can arise because of genetic factors independent of the r factor being eliminated. a fraction of the infected but unconverted r(+) cells ...19724591485
sequence analysis of the lysin gene region of the prolate lactococcal bacteriophage c2.approximately 80% of the genome of the prolate-headed lactococcal bacteriophage c2 was cloned into shuttle vectors psa3 and pfx3 in escherichia coli and transferred to lactococcus lactis. a 1.67-kilobase ecorv fragment containing the gene for the phage lysin was identified and the position and orientation of the phage lysin gene in the physical map of the phage were determined. the phage lysin was expressed in e. coli and its sequence was determined and compared with the sequences of other bacte ...19938221377
reactions of mitochondrial cruciform cutting endonuclease 1 (cce1) of yeast saccharomyces cerevisiae with branched dnas in vitro.cruciform-cutting endonuclease 1 (cce1) is an x-solvase from yeast saccharomyces cerevisiae [kleff, s., kemper, b. & sternglanz, r. (1992) embo j. 11, 699-704]. we report here the purification of the cloned enzyme cce1 to near homogeneity from over-expressing escherichia coli cells. the purified protein has a globular shape and an apparent molecular mass of 38 kda. cce1 reacts specifically with branched dnas, preferably with four-armed cruciforms. the enzyme linearizes native supercoiled dna by ...19968665955
base-pairing properties of n4-methoxydeoxycytidine 5'-triphosphate during dna synthesis on natural templates, catalyzed by dna polymerase i of escherichia coli.n4-methoxydeoxycytidine 5'-triphosphate (mo4dctp) was synthesized by reaction of dctp with methoxyamine and then purified by high-performance liquid chromatography (hplc) and used to analyze the specificity of mo4dcmp incorporation during polymerization on natural templates, catalyzed by dna polymerase i of escherichia coli. elongation of synthetic 5'-32p-labeled primers, annealed to single-stranded dna of bacteriophage m13, was carried out in the presence of only three of the four normal dntps; ...19853888268
binding of the dimeric deinococcus radiodurans single-stranded dna binding protein to single-stranded dna.deinococcus radiodurans single-stranded (ss) dna binding protein (drssb) originates from a radiation-resistant bacterium and participates in dna recombination, replication, and repair. although it functions as a homodimer, it contains four dna binding domains (ob-folds) and thus is structurally similar to the escherichia coli ssb (ecossb) homotetramer. we examined the equilibrium binding of drssb to ssdna for comparison with that of ecossb. we find that the occluded site size of drssb on poly(dt ...201020795631
unit-length, single-stranded circular dnas of both polarity of begomoviruses are generated in escherichia coli harboring phage m13-cloned begomovirus genome with single copy of replication origin.replication of genomic dnas of plant-pathogenic begomoviruses has been demonstrated in prokaryotes, which supported the possibility of analyzing dna replication process of begomoviruses in bacteria. however, previous studies indicated that the replication of begomovirus dnas in prokaryotes requires tandem constructs of viral genomes with at least two copies of the origin of replication (ori). in this study, phage m13 vector harboring the unit-length genome with only a single copy of ori of a mon ...200717204346
inhibition of bacterial conjugation by phage m13 and its protein g3p: quantitative analysis and model.conjugation is the main mode of horizontal gene transfer that spreads antibiotic resistance among bacteria. strategies for inhibiting conjugation may be useful for preserving the effectiveness of antibiotics and preventing the emergence of bacterial strains with multiple resistances. filamentous bacteriophages were first observed to inhibit conjugation several decades ago. here we investigate the mechanism of inhibition and find that the primary effect on conjugation is occlusion of the conjugat ...201121637841
identification and safety evaluation of bacillus species occurring in high numbers during spontaneous fermentations to produce gergoush, a traditional sudanese bread snack.gergoush is a naturally fermented sudanese bread snack produced in three fermentation steps (primary starter, adapted starter and final dough), followed by three baking steps for a half to one hour at above 200 °c. this study examines the microbiota of two sets of fermentations performed at a traditional production site in khartoum, sudan in 2006 and 2009, respectively. in 2006 four different milk/legume based primary starters (faba bean, chick pea, lentil and white bean) were sampled in order t ...201121429611
analytical model for determination of parameters of helical structures in solution by small angle scattering: comparison of reca structures by sans.the filament structures of the self-polymers of reca proteins from escherichia coli and pseudomonas aeruginosa, their complexes with atpgammas, phage m13 single-stranded dna (ssdna) and the tertiary complexes reca::atpgammas::ssdna were compared by small angle neutron scattering. a model was developed that allowed for an analytical solution for small angle scattering on a long helical filament, making it possible to obtain the helical pitch and the mean diameter of the protein filament from the ...200312606054
membrane assembly from purified components. ii. assembly of m13 procoat into liposomes reconstituted with purified leader peptidase.the major coat protein of coliphage m13 is an integral protein of the e. coli plasma membrane prior to its assembly into new virus particles. it is generated from its precursor, procoat, by a membrane-bound leader peptidase. we now describe the reconstitution of a highly purified preparation of this enzyme into vesicles of e. coli phospholipids. these vesicles bind procoat made in vitro and procoat isolated from in vitro synthesis. both the crude and the purified substrates were converted post-t ...19817026043
real-time kinetics of restriction-modification gene expression after entry into a new host cell.most type ii restriction-modification (r-m) systems produce separate restriction endonuclease (rease) and methyltransferase (mtase) proteins. after r-m system genes enter a new cell, protective mtase must appear before rease to avoid host chromosome cleavage. the basis for this apparent temporal regulation is not well understood. pvuii and some other r-m systems appear to achieve this delay by cotranscribing the rease gene with the gene for an autogenous transcription activator/repressor (the 'c ...200818334533
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