Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| processive proofreading is intrinsic to t4 dna polymerase. | dna replication occurs in vivo with very high processivity, meaning that the replication complex assembles at the origin(s) of replication and then performs template-directed synthesis of dna over virtually the entire genome without dissociation. such processivity also characterizes reconstituted replication holoenzyme complexes in vitro. however, the isolated dna polymerases are much less processive, especially under physiological conditions. in this paper we monitor the degree of processivity ... | 1992 | 1629215 |
| consequences of molecular engineering enhanced dna binding in a dna repair enzyme. | facilitated one-dimensional diffusion is a general mechanism utilized by several dna-interactive proteins as they search for their target sites within large domains of nontarget dna. t4 endonuclease v is a protein which scans dna in a nonspecifically bound state and processively incises dna at ultraviolet (uv)-induced pyrimidine dimer sites. an electrostatic contribution to this mechanism of target location has been established. previous studies indicate that a decrease in the affinity of endonu ... | 1992 | 1567866 |
| recombinant human immunodeficiency virus type 1 nucleocapsid (ncp7) protein unwinds trna. | the nucleocapsid protein (nc) of all animal retroviruses, encoded by the gag gene, is the major structural protein of the core ribonucleoprotein complex, bound to genomic rna in mature virions. nc is also thought to play one or more accessory roles in reverse transcription. mature nc (p7nc) from human immunodeficiency virus type 1 (hiv-1) is a 71-amino acid, basic protein which contains two cys3his zn(ii) retroviral-type zinc finger domains. herein, we describe the subcloning and expression of h ... | 1992 | 1551877 |
| are there highly conserved dna polymerase 3'----5' exonuclease motifs? | it was proposed by bernad et al. [cell 59 (1989) 219-228] and blanco et al. [gene 100 (1991) 27-38] that the 3'----5' exonuclease (exo) domain of escherichia coli dna polymerase i (poli) is structurally and functionally conserved among prokaryotic and eukaryotic dna polymerases. the basis for this claim is the presence of three short peptide sequences in many dna polymerases that resemble poli sequences that have been shown by x-ray crystallographic and genetic engineering studies to be metal io ... | 1992 | 1551593 |
| effect of escherichia coli nusg function on lambda n-mediated transcription antitermination. | the escherichia coli nus factors act in conjunction with the bacteriophage lambda n protein to suppress transcription termination on the lambda chromosome. nusa binds both n and rna polymerase and may also interact with other nus factors. to search for additional components of the n antitermination system, we isolated host revertants that restored n activity in nusa1 mutants. one revertant, nusg4, was mapped to the rif region of the e. coli chromosome and shown to represent a point mutation near ... | 1992 | 1531224 |
| critical functional role of the cooh-terminal ends of longitudinal hydrophobic strips in alpha-helices of t4 lysozyme. | the sensitivity of bacteriophage t4 lysozyme function to amino acid substitutions at defined positions in and around the longitudinal, hydrophobic strips of 9 alpha-helices was assessed after systematic replacement of each residue in the protein with a series of 13 amino acids. the hydrophobic strips were defined by identifying the longitudinal sectors in the helices with the highest mean residue hydrophobicities. sensitivity to mutation (the percentage of replacements leading to loss of functio ... | 1992 | 1517218 |
| in vitro characterization of repair synthesis initiated by t4 endonuclease v on a synthetic dna substrate. | the size of the repair patch produced by e. coli dna polymerase (pol i) following the removal of a pyrimidine dimer from dna in response to the nicking activity of t4 endonuclease (t4 endo v) was determined. a 48-bp dna containing a pyrimidine dimer at a defined location was labelled in the damaged strand and incubated with t4 endo v and e. coli endonuclease iv. subsequently, dna synthesis by dna pol i was carried out in the presence of four dntps, atp and dna ligase. analysis of the reaction pr ... | 1992 | 1512008 |
| molecular characterisation of a dna ligase gene of the extremely thermophilic archaeon desulfurolobus ambivalens shows close phylogenetic relationship to eukaryotic ligases. | a 3382 bp fragment containing a gene for a dna ligase from the extremely thermophilic, acidophilic, and facultatively anaerobic archaeon (archaebacterium) desulfurolobus ambivalens was cloned and sequenced. the deduced amino acid sequence (600 amino acids, 67619 molecular weight) showed 30-34% sequence identity with the atp-dependent eucaryal (eukaryotic) dna ligases of schizosaccharomyces pombe, saccharomyces cerevisiae, the human dna ligase i, and with the vaccinia dna ligase. distant similari ... | 1992 | 1437556 |
| cloning, sequencing, overproduction, and purification of m. cvibi (gantc) methyltransferase from chlorella virus nc-1a [corrected]. | we have cloned and sequenced the cvibim gene from chlorella virus nc-1a by selecting for the modification phenotype. the modification gene was cloned on a 7-kb bamhi fragment inserted into the bamhi site of the puc13 plasmid. the cvibim gene was localized at the 3' end of this fragment. sequencing of this region revealed a large open reading frame that codes for methyltransferase (mtase; symbol m.) (predicting 260 amino acids). m.cvibi (gantc) aa sequence is homologous to m.dam(gatc), m.dpnii(ga ... | 1992 | 1427082 |
| roles of cys148 and asp179 in catalysis by deoxycytidylate hydroxymethylase from bacteriophage t4 examined by site-directed mutagenesis. | the proposed roles of cys148 and asp179 in deoxycytidylate (dcmp) hydroxymethylase (ch) have been tested using site-directed mutagenesis. ch catalyzes the formation of 5-(hydroxymethyl)-dcmp, essential for dna synthesis in phage t4, from dcmp and methylenetetrahydrofolate. ch resembles thymidylate synthase (ts), an enzyme of known three-dimensional structure, in both amino acid sequence and the reaction catalyzed. conversion of cys148 to asp, gly, or ser decreases ch activity at least 10(5)-fold ... | 1992 | 1420151 |
| the distribution of uv damage in the laci gene of escherichia coli: correlation with mutation spectrum. | we have determined the uv (254 nm) damage distribution in the transcribed and non-transcribed strands of the i-d region of the escherichia coli laci gene. the locations of replication blocking lesions were revealed as termination sites of t7 dna polymerase and/or t4 dna polymerase 3'-5' exonuclease. termination products, i.e. both cyclobutane pyrimidine dimers and 6-4 photoproducts, were resolved and analysed on an automated dna sequencer. these two major photoproducts are not randomly distribut ... | 1992 | 1383713 |
| three-dimensional structure of the beta subunit of e. coli dna polymerase iii holoenzyme: a sliding dna clamp. | the crystal structure of the beta subunit (processivity factor) of dna polymerase iii holoenzyme has been determined at 2.5 a resolution. a dimer of the beta subunit (m(r) = 2 x 40.6 kd, 2 x 366 amino acid residues) forms a ring-shaped structure lined by 12 alpha helices that can encircle duplex dna. the structure is highly symmetrical, with each monomer containing three domains of identical topology. the charge distribution and orientation of the helices indicate that the molecule functions by ... | 1992 | 1349852 |
| ligation-independent cloning of glutathione s-transferase fusion genes for expression in escherichia coli. | a plasmid vector has been constructed that allows the ligation-independent cloning of cdnas in any reading frame and directs their synthesis in escherichia coli as glutathione s-transferase-linked fusion proteins. the cloning procedure does not require restriction enzyme digestion of the target sequence and does not introduce any additional sequences between the thrombin cleavage site and the foreign protein. extended single-stranded tails complementary between the vector and insert, generated b ... | 1992 | 1339364 |
| evidence that recbc-dependent degradation of duplex dna in escherichia coli recd mutants involves dna unwinding. | infection of escherichia coli with phage t4 gene 2am was used to transport 3h-labeled linear duplex dna into cells to follow its degradation in relation to the cellular genotype. in wild-type cells, 49% of the dna was made acid soluble within 60 min; in recb or recc cells, only about 5% of the dna was made acid soluble. remarkably, in recd cells about 25% of the dna was rendered acid soluble. the dna degradation in recd cells depended on intact recb and recc genes. the degradation in recd cells ... | 1992 | 1322885 |
| a system of transposon mutagenesis for bacteriophage t4. | we have developed a system of transposon mutagenesis for bacteriophage t4. the transposon is a plasmid derivative of tn5 which contains the essential t4 gene 24, permitting a direct selection for transposition events into a gene 24-deleted phage. the transposition occurred at a frequency of only 10(-7) per progeny phage, even though a dam- host was used to increase transposition frequency. phage strains with a transposon insert were distinguished from most pseudorevertants of the gene 24 deletio ... | 1992 | 1322484 |
| replication inhibition and translesion synthesis on templates containing site-specifically placed cis-diamminedichloroplatinum(ii) dna adducts. | a series of site-specifically plantinated, covalently closed circular m13 genomes (7250 bp) was constructed in order to evaluate the consequences of dna template damage induced by the anticancer drug cis-diamminedichloroplatinum(ii) (cis-ddp). here are reported the synthesis and characterization of genomes containing the intrastrand cross-linked adducts cis-[pt(nh3)2[d(apg)-n7(1),-n7(2)]], cis-[pt-(nh3)2[d(gpcpg)-n7(1),-n7(3)]], and trans-[pt(nh3)2[d(cpgpcpg)-n3(1),-n7(4)]]. these constructs, as ... | 1992 | 1314653 |
| improved band shift assay for the simultaneous analysis of protein-dna interactions and enzymatic functions of dna polymerases. | a simple method to assay the major properties of dna polymerases such as template binding, polymerase and exonuclease activities in one step is exemplified with the dna polymerases of e. coli, bacteriophage t4 and herpes simplex virus. combining the advantages of the band-shift assay with the resolving power of polyacrylamide gradient gel electrophoresis, the procedure is particularly useful for a rapid functional analysis of mutant polymerases as well as inhibitors of dna replication. | 1992 | 1314195 |
| recovery of the accumulation ability of thiomethyl-beta-galactoside in escherichia coli after bacteriophage t4 infection. | effects of uv-irridiated and unirradiated t4 phage infection on the beta-galactoside accumulation ability in eschericia coli have been examined by the use of 14c-labeled thiomethyl-beta-galactoside (tmg). under conditions where a synchronous adsorption of phage takes place, the cellular ability for tmg accumulation is found to be largely inhibited immediately after phage adsorption, but it recovers with time to a new level, which is dependent on the multiplicity of infection. when cells are infe ... | 1976 | 1255845 |
| host membrane lipid synthesis is not required for successful phage t4 infection. | 1976 | 1108415 | |
| the role of replication proteins in the regulation of bacteriophage t4 transcription. i. gene 45 and hydroxymethyl-c-containing dna. | 1975 | 1104860 | |
| the biology of bacteriophage t4 transfer rnas. | 1975 | 1104087 | |
| the repair of ultraviolet damage by phage t4: the role of the early phage genes. | 1975 | 1103821 | |
| effect of t4 modification of host valyl-trna synthetase on enzyme action in vivo. | 1975 | 1103443 | |
| direct selection of mutants restricting efficiency of suppression and misreading levels in e. coli b. | we describe a method for the direct selection of e. coli mutants restricting efficiency of suppression and misreading levels using a t4-coded nonsense suppressor. one mutant isolated has the phenotype expected for a restrictive mutant and may be ribosomal. other possibilities are discussed. | 1975 | 1102920 |
| relaxation complexes of poasmid dna and protein. iii. association of protein with the 5' terminus of the broken dna strand in the relaxed complex of plasmid cole1. | the location of the protein in the open circular dna form of the cole1 dna-protein relaxation complex, induced by treatment with sodium dodecyl sulfate, has been studied using several enzymes of dna metabolism. escherichia coli exonucleases i and iii are able to degrade extensively the nicked strand of the relaxed complex from the 3' end. dna polymerase i can initiate synthesis using the relaxed complex as template-primer and specifically extends the 3' end of the nicked strand. the 5' end of th ... | 1975 | 1102545 |
| analysis of bacteriophage t4 chloramphenicol rna by dna-rna hybridization and by cell-free protein synthesis, and the effect of escherichia coli polarity-suppressing alleles on its synthesis. | 1975 | 1100847 | |
| repetitive dna replication of the incomplete genomes of phage t4 petite particles. | the genomes of petite t4 phage particles presumably cannot circularize because they are deficient for a significant terminal segment and hence not terminally redundant like normal t4 genomes. combined density- and 32p-labeling shows that the majority of such deficient dna molecules can nevertheless replicate their entire length. furthermore, the density-shift technique shows that replicated parental strands can exchange their partners for new light strands, indicating that noncircularized t4 dna ... | 1975 | 1099579 |
| carbon loss during irradiation of t4 bacteriophages and e. coli bacteria in electron microscopes. | 1975 | 1097727 | |
| the nucleotide sequence of the dimeric precursor to glutamine and leucine transfer rnas coded by bacteriophage t4. | 1975 | 1097716 | |
| recovery of polysome function of t4-infected escherichia coli after brief treatment with chloramphenicol and rifampin. | t4-infected escherichia coli cells briefly exposed to rifampin, or to rifampin plus chloramphenicol, were capable of protein synthesis for some time after removal of the antibiotics, although ribonucleic acid synthesis was irreversibly inhibited. partially completed peptides trapped on polysomes by high levels of chloramphenicol were eventually completed after removal of the drug, as demonstrated by subjecting labeled peptides from appropriate polysome regions to polyacrylamide disc gel electrop ... | 1975 | 1096805 |
| packaging of dna into t4 bacteriophage: exclusion of host dna despite the absence of both host dna degradation and nuclear disruption. | 1975 | 1096456 | |
| bacteriophage t7 deoxyribonucleic acid replication in vitro. purification and properties of the gene 4 protein of bacteriophage t7. | the t7 gene 4 protein, a protein known from genetic analysis to participate in phage dna replication in vivo, has been purified approximately 500-fold with an in vitro complementation assay. the protein, purified from cells infected with a t7 gene 4 temperature-sensitive mutant, is thermolabile, establishing that the complementation activity is in the protein product of the phage gene 4. the purified protein has no detectable nuclease, dna polymerase, or rna polymerase activity. however, in addi ... | 1975 | 1095580 |
| proceedings: modification of e. coli rna polymerase induced by t4 phage infection. | 1975 | 1094019 | |
| transcription of azotobacter phage deoxyribonucleic acid. salt-dependent equilibrium between steps in initiation. | the transcription of azotobacter phage a21 dna by escherichia coli or azotobacter vinelandii rna polymerase differs from that of some other dnas in its inhibition by moderate concentrations of kcl. this characteristic results in an apparent low template activity for this dna as compared with t4 dna under standard assay conditions. from an analysis of the dependence of the various steps in initiation on kcl it is concluded that the effect is exerted on an equilibrium between an inactive polymeras ... | 1975 | 1091643 |
| isolation and partial characterization of three escherichia coli mutants with altered transfer ribonucleic acid methylases. | seven transfer ribonucleic acid (trna) methylase mutants were isolated from escherichia coli k-12 by examining the ability of rna prepared from clones of unselected mutagenized cells to accept methyl groups from s-adenosylmethionine catalyzed by crude enzymes from wild-type cells. five of the mutants had an altered uracil-trna methylase; consequently their trna's lacked ribothymidine. one mutant had trna deficient in 7-methylguanosine, and one mutant contained trna lacking 2-thio-5-methylaminome ... | 1975 | 1091626 |
| transcription of bacteriophage t4 genome in vitro. heterogeneity of rna polymerase in crude extracts of normal and t4-infected escherichia coli b. | in order to obtain rna polymerase preparations carrying the necessary specificity determinants to transcribe the delayed-early genes of bacteriophage t4, crude extracts of uninfected and t4-infected escherichia coli were fractionated in glycerol gradients of low ionic strength. in contrast to the reported sedimentation behavior of the purified enzyme, the rna polymerase activity in crude extracts of normal and infected cells sedimented heterogeneously over a wide range of sedimentation coefficie ... | 1975 | 1091288 |
| comparison of the effects of bacteriophage t4 infection and n-ethylmaleimide on the translational specificity of escherichia coli ribosomes. | 1975 | 1091211 | |
| characterization of new regulatory mutants of bacteriophage t4. ii. new class of mutants. | new mutants of bacteriophage t4 that overproduce the enzyme dihydrofolate reductase were investigated. unlike previously described overproducers of this enzyme (johnson and hall, 1974), these mutants did not overproduce deoxycytidylate deaminase. overproduction of dihydrofolate reductase by the new mutants occurred because enzymatic activity continued to increase for a longer period of time in cells infected by the mutants than in cells infected by wild-type phage. this continued increase occurr ... | 1975 | 1090753 |
| bacteriophage-host interaction and restriction of nonglucosylated t6. | nonglucosylated t6 phage (t6gtam 16am30, hereafter called t6alpha gt-) were found to have two structural anomalies when compared with wild-type t6. the dna of t6alpha gt- phage contains single-strand interruptions. these can be seen both during infection, in the pool of replicating dna, and in dna extracted from purified phage. in addition, the sodium dodecyl sulfate-polyacrylamide gel pattern of t6alpha gt- phage structural proteins reveals a protein band not found in t6. the altered protein ha ... | 1975 | 1090750 |
| cleavage of nonglucosylated bacteriophage t4 deoxyribonucleic acid by restriction endonuclease eco ri. | dnas lacking the glucosyl modification (glc-) and additionally lacking the 6-methylaminopurine (n6-methyladenine) modification (glc-, meade-) were prepared from appropriate t4 mutants. these dnas were cleaved by the purified restriction endonuclease eco ti from escherichia coli. normally modified dna (glc+, meade+) was not attached. the eco rii and the hemophilus enzymes hin dii and hin diii do not attack glc-, meade- t dna, possibly due to the presence of 6-hydroxymethylcytosine. eco ri produce ... | 1975 | 1090619 |
| reconstruction of bacteriophage t4 dna replication apparatus from purified components: rolling circle replication following de novo chain initiation on a single-stranded circular dna template. | the protein products of t4 bacteriophage genes 41, 43, 45, 44, and 62 have been purified to near homogeneity using an assay which measures their stimulation of dna synthesis in a crude lysate of escherichia coli cells in fected by an appropriate mutant phage. when all of these proteins and t4 gene 32 protein are incubated in the presence of deoxyribonucleoside and ribonucleoside triphosphates, extensive dna synthesis occurs on both single and double-stranded dna templates. analysis of this in vi ... | 1975 | 1061070 |
| human globin messenger rna: importance of cloning for structural analysis. | the sequence of most of the human beta globin messenger rna and large sections of the alpha globin messenger rna has been determined. partly because of genetic polymorphism, it was necessary to clone globin complementary dna in order to extend the analysis. purified human fetal globin messenger rna was isolated and used as a template by reverse transcriptase to produce duplex complementary dna molecules. these molecules were linked in vitro to plasmid dna by use of t4 ligase in the presence of e ... | 1977 | 847468 |
| specificity of bacterial ribosomes and messenger ribonucleic acids in protein synthesis reactions in vitro. | ribosomes from two gram-negative bacteria translated f2 rna, t4 early mrna, mrna from three gran-negative bacteria, and mrna from six gram-positive bacteria; ribosomes from three gram-positive bacteria translated mrna from the gram-positive strains, but did not translate the other mrnas. ribosomes from the gram-negative bacterium escherichia coli translated synthetic poly(u,g) but ribosomes from the gram-positive bacterium clostridium pasteurianum translated poly(u,g) very poorly, mrna from gram ... | 1976 | 816792 |
| heterologous deoxyribonucleic acid uptake and complexing with cellular constituents in competent bacillus subtilis. | with competent cultures of bacillus subtilis the uptake of escherichia coli deoxyribonucleic acid (dna) is about 50% that for homologous dna. uptake of phage t6 dna, if any, is of the order of 7%, while nonglucosylated phage t6 (t6) dna is taken up almost as effectively as homologous dna. both t6 and t4 dna interfere only minimally with uptake of homologous dna; by contrast, t6 dna competes with homologous dna as effectively as the latter itself. these results indicate that the glucose residues ... | 1975 | 811646 |
| construction and characterization of a chimeric plasmid composed of dna pfrom escherichia coli and drosophila melanogaster. | a chimeric plasmid has been constructed in vitro from colicin e1 factor (col e1), nontransmissible r-factor rsf-1010, and drosophila melanogaster dnas by the sequential action of escherichia coli endonuclease ri(eco ri) and t4 phage dna ligase. the chimeric plasmid was assembled in two stages--first, a composite plasmid consisting of col e1 and rsf 1010 was constructed, followed by partial digestion of the composite with eco ri (in order to open one of the susceptible cleavage sites) and ligatio ... | 1975 | 807234 |
| revertants of double opal-mutants of bacteriophage t4. | revertants of double opal-mutants of bacteriophage t4 have been obtained. the properties of these revertants suggest that reversion of double opal-mutants is effected by the activity of some gent-suppressor appeared in the phage genome. restriction of these revertants by streptomycin-resistant bacterial strains shows that the suppression of the opal-mutants is realized at translation. | 1976 | 799254 |
| [biology of spheroplast- and protoplast-like types of l-forms of escherichia coli k12 converted with penicillin]. | a total of 21 strains of stable l-forms were obtained under the action of penicillin on various hfr and f- strains of e. coli k12. three morphological types of the l-forms obtained differed by the character of the cell elements, sensitivity to chemical agents, antibiotics and to t4 and t6 phages. cell wall was revealed in one type of the l-forms, but the rest l-form types were devoid of the cell walls. reference of the l-forms which preserved the cell wall to the spheroplastic type, and the l-fo ... | 1976 | 795246 |
| the sucrose gradient and native dna s20,w, an examination of measurement problems. | sedimentation coefficients of t7, t2h and t4 dna were determined with isokinetic sucrose gradients in both 0.1 m and 1 m nacl. the s values were completely equivalent to those measured by analytical ultracentrifuge and no reduction of s20,w was observed due to the presence of sucrose (anomalous sedimentation). s20,w values are calculated on the basis of both partial specific volume (v) and apparent specific volume (0). using the latter value s20,w molecular weight relations are derived for 0.1 m ... | 1976 | 793631 |
| biochemical construction of specific chimeric plasmids from cole1 dna and unfractionated escherichia coli dna. | a series of chimeric plasmids was constructed using colicinigenic factor e1 (cole1) dna as the replicon and dna fragments carrying the galactose or tryptophan operons from e. coli. restriction endonuclease ecori digests of cole1 dna and various dnas containing the trp or gal operons were joined by t4 polynucleotide ligase [polynucleotide synthetase (atp), poly(deoxyribonucleotide):poly(deoxyribonucleotide) ligase (amp-forming), ec 6.5.1.1]. chimeric plasmids carrying the desired genes were selec ... | 1976 | 792875 |
| regulation of gene 32 expression during bacteriophage t4 infection of escherichia coli. | the gene 32 protein of the bacteriophage t4 plays an important role in genetic recombination, dna repair, and dna replication; the protein functions in these processes by virtue of a strong binding capacity for single-stranded dna. during infections of escherichia coli by bacteriophage carrying amber of temperature-sensitive mutations in gene 32, the altered gene 32 protein (that is, the amber fragment of the missense polypeptide) is synthesized at greatly elevated rates. during infections by ph ... | 1976 | 791947 |
| properties of condensed bacteriophage t4 dna isolated from escherichia coli infected with bacteriophage t4. | methods developed for isolating bacterial nucleoids were applied to bacteria infected with phage t4. the replicating pool of t4 dna was isolated as a particle composed of condensed t4 dna and certain rna and protein components of the cell. the particles have a narrow sedimentation profile (weight-average s=2,500s) and have, on average, a t4 dna content similar to that of the infected cell. their dimensions observed via electron and fluorescence microscopy are similar to the dimensions of the int ... | 1976 | 787557 |
| replication of bacteriophage t4 dna in vitro. i. basic properties of the system. | a new in vitro system for t4 dna replication was developed by concentrating cell lysates on cellophane disks. the time course of [3h]dttp incorporation into dna by the system was separated into two phases: one was a very rapid incorporation which was terminated within 2 min (phase i reaction), and the other was a slow but continuous incorporation thereafter (phase ii reaction). more than half of the phase i reaction product was escherichia coli dna, but the phase ii reaction was mostly t4 dna. p ... | 1976 | 785023 |
| properties and structure of a gene 24-controlled t4 giant phage. | 1976 | 781276 | |
| t4 dna injection. ii. protection of entering dna from host exonuclease v. | 1976 | 779243 | |
| purification of a proteolytic enzyme from t4-infected escherichia coli cells. | 1976 | 779237 | |
| cleavage of t4-induced proteins during phage morphogenesis: characterization of peptides. | polypeptides of low mol. wt. have been extracted from t4 coliphages and from escherichia coli b cells infected with a wild type and various amber mutants of bacteriophage t4. six peptides were fractionated by chromatography on phosphocellulose: three of them were cleaved from proteins synthesized late in infection and related to phage head. the remaining three peptides have been shown to arise from early-labelled phage-induced proteins. two of these six small petide fragments were found in the h ... | 1976 | 778336 |
| lipopolysaccharide-deficient, bacteriophage-resistant mutants of escherichia coli k-12. | bacteriophage-resistant mutants isolated and classified in a previous study were examined for alterations in their lipopolysaccharide (lps) composition, and properties likely to be affected by alterations in lps composition were studied. it was found that many of the mutants of the ktw (k2-resistance), ttk (t2, t4, or k19 resistance), bar (bacteriophage), wrm (wide-range mutants), and miscellaneous resistance groups were altered in their response to a series of antibiotics and to two lps-specifi ... | 1976 | 776951 |
| induced mutagenesis in bacteriophage t4 growing in strains of e. coli with altered rna-polymerase. | enhanced reversion frequencies of t4 r mutants in e. coli strains with altered rna polymerase have been obtained. the results reported have confirmed previous data on the effect of rna-polymerase on the process of mutagenesis [2]. no such effect has been found in the course of studies of the recombination process. | 1976 | 775324 |
| a study of possible mechanisms of the rna-polymerase involement in mutagenesis in phage t4. | spontaneous and induced mutation frequencies of phage t4 have been measured in escherichia coli strains containing altered rna-polymerase. in the strain e. coli rif-r stl-r, with double rna-polymerase mutation, spontaneous reversion rates were increased in different mutants of phage t4. the study of base analogues mutagenesis in ruv mutants of phage t4 has shown that the introduction of rna-polymerase mutations did not increase reversion rates in a mutant of frame-shift type but enhanced the rat ... | 1976 | 775319 |
| dna crosslinks, single-strand breaks and effects on bacteriophage t4 survival from tritium decay of (2-3h)adenine, (8-3h)adenine and (8-3h)guanine. | 1976 | 772217 | |
| studies on phage internal proteins: formation of internal protein - t2 dna complexes in vivo. | internal proteins, synthesized in t2-infected escherichia coli b cells were recovered from bacterial membranes during the early stages of infection. approx. 15 min after the onset of infection, t2 and t4 internal proteins were released from the bacterial membranes and sedimented along with newly synthesized phage dna. internal protein-dna complexes were also obtained by chromatography on hydroxylapatite columns. internal proteins were not released from bacterial membranes after infection with am ... | 1976 | 772169 |
| mechanism localisation and control of restriction cleavage of phage t4 and lambda chromosomes in vivo. | the primary action of restriction endonuclease, cleaving infecting dna, has been demonstrated in vivo. this primary cleavage is followed rapidly by hydrolysis of the cleaved dna at its newly exposed termini. infecting viruses can inactivate cytoplasmic and membrane restriction endonucleases to prevent cleavage of unmodified dna replicas. | 1976 | 768782 |
| [effect of restricting the action of an amber-mutation suppressor contained in bacteriophage t4 genome]. | the action of a bacteriophage suppressor can be restricted due to mutations arising in the genome of the host bacteria. bacterial strains escherichia coli bn and can were isolated in which a complete restriction of the action of phage suppressor psu+ took place. in thees strains obtained the restriction of serin-specific phage suppressors psu + a and psu + b is brought about. the action of bacteriophage suppressor su3+ containing in e. coli can is not abolished in this strain. the abolish of the ... | 1975 | 767202 |
| genetic control of bacteriophage t4 baseplate morphogenesis. i. sequential assembly of the major precursor, in vivo and in vitro. | 1975 | 765481 | |
| gene expression and stability of mrna affected by dna-arrested synthesis in gene 59, 46, and 47 mutants of bacteriophage t4. | the effect of bacteriophage t4 gene 59 mutations (dna-arrested synthesis) on kinetics of dna synthesis, gene expression, and stability of mrna has been studied. when escherichia coli b was infected by a t4 gene 59 mutant, dna synthesis proceeded to increase linearly after initiation, but started to decrease at 8 min and was completely arrested at 12 min at 37 degrees c. at various incubation temperatures (20 to 42 degrees c), the initial rates and times of arrest of dna synthesis were different, ... | 1978 | 702642 |
| [interaction between alkaloids of claviceps purpurea and development of some bacteria and bacteriophages. preliminary experiments]. | it has been tested the bacteriolytic activity and the interaction among the development of the bacteriophage t4 and ergot alkaloids. it has been determined a bacteriolytic action on the bacterial stub "e. coli host of bacteriophage t4. it exist an interaction also among such alkaloids and the development of the bacteriophage t4, which appears through an increase of the quantity of lysis areas, becoming evident in solid bodies containing the lysing bacterium. further researches with other bacteri ... | 1979 | 400107 |
| platinum(ii) complexes block the entry of t4 phage dna into the host cells. | the efficiency of multiplicity reactivation of t4 particles inactivated by platinum(ii) complexes is very low. the same is true for marker rescue and functional survival of genes. this can be at least partly explained by the inability of most inactivated virus particles to introduce their dna into the host cells as demonstrated by electron microscopy. conformational changes in the dna, formation of dna-dna and dna-protein cross-links and the damage of proteins participating in the injection proc ... | 1979 | 398750 |
| nucleotide sequence of the region required for maintenance of colicin e1 plasmid. | plasmids carrying various portions of colicin e1 plasmid (cole1) dna have been isolated in an attempt to determine the regions of cole1 dna which are required for maintenance of the plasmid in bacteria. to construct the plasmids, the dna of a cole1 derivative that contains a gene which controls ampicillin resistance was cleaved by the restriction endonuclease haeii. the digestion products were joined by t4 dna ligase and then used to transform bacteria to ampicillin resistance. the plasmid deriv ... | 1979 | 393952 |
| [asymmetry in the frequencies of reciprocal recombinants in crosses of t4 phage riib mutants]. | the frequencies of reciprocal recombinants in crosses between riib mutants of t4 phage were shown to differ from each other. in terms of the correction model, this asymmetry of genetic recombination was used to measure the comparative correctability of the mismatched regions to the wild type and to the mutant alleles. the data obtained are in quantitative agreement with the analogous values for the same mismatched regions determined by comparison of the markers located at the same site. this str ... | 1979 | 391644 |
| purification and some properties of deoxyribonuclease whose synthesis is controlled by gene 49 of bacteriophage t4. | an enzyme which specifically cleaves very-fast-sedimenting dna of bacteriophage t4 is synthesized after infection of t4, and its synthesis is controlled by gene 49 [1,2]. this enzyme has been proved to be a dnase [2]. we have purified this dnase 3000-fold from extracts of e. coli infected with t4. the purified preparation was practically free from other dnases, and the dnase activity was not detectable in cells infected with a mutant defective in gene 49. the enzyme activity from cells infected ... | 1979 | 389625 |
| the effect of template secondary structure on vaccinia dna polymerase. | vaccinia virus dna polymerase will utilize a substrate consisting of phi x174 dna primed with a strand of a unique restriction fragment, but the reaction is inefficient. examination of the reaction products by alkaline agarose gel electrophoresis revealed a few discrete fragments, each corresponding to an extended primer strand. this result implies that specific barriers exist on the phi x174 template which impede, but do not completely halt, the progress of the enzyme. only a few per cent of th ... | 1979 | 381293 |
| restriction in vivo. iii. general effects of glucosylation and restriction on phage t4 gene expression and replication. | 1979 | 380145 | |
| [topological model of bacteriophage-t4 dna replication]. | the structure and function of the dna--membrane complex in e. coli cells infected with bacteriophage t4 was studied. the dna--membrane complex was isolated from the cells pulse or uniformly labeled with 3h-thymidine, fractionated by detergent treatment and separated on a discontinuous sucrose gradient. the attachment of small dna fragments to the plasma membrane was analysed. replicating bacteriophage t4 dna was reversibly associated with the cytoplasmic membrane in the wall/membrane adhesion zo ... | 1977 | 377048 |
| dna replication with bacteriophage t4 proteins. purification of the proteins encoded by t4 genes 41, 45, 44, and 62 using a complementation assay. | the proteins encoded by bacteriophage t4 genes 41, 45, 44, and 62 are known from the genetic studies of epstein et al. ((1963) cold spring harbor symp. quant. biol. 28, 375--394) to be required for viral dna synthesis. a convenient assay for each of these proteins is described which is based on the specific stimulation by each protein of dna synthesis in extracts of escherichia coli infected with mutants of bacteriophage t4 unable to make that protein. the t4 41 protein, 45 protein, and the comp ... | 1979 | 376524 |
| [selective binding of oligoribonucleotides by t7 phage induced rna-polymerase]. | it was shown previously that e. coli rna-polymerase being incubated with the random oligonucleotide mixtures of definite length binds certain oligoribonucleotides with the length greater than or equal to 5 nucleotides. the data presented demonstrate that t7 phage induced rna-polymerase (t7 rna-polymerase) also binds selectively oligoribonucleotides beginning from pentaribonucleotides. from the random mixtures of penta-, hexa-, hepta-, octa-, nona- and decaribonucleotides the hepta- and octaribon ... | 1978 | 370554 |
| s1 nuclease as a probe for the conformation of a dimeric trna precursor. | we have employed s1 nuclease to probe the structure of an intermediate in trna biosynthesis available only in radiochemical purity. the dimeric precursor to trnagln and trnaleu from bacteriophage t4 was digested with the single-strand specific nuclease, and the products of the reaction were compared with the s1 digestion products of the mature cognate trna's. quantitation and sequence analysis of the products revealed that the location and accessibility of s1 cleavage sites in the precursor were ... | 1979 | 369598 |
| construction and properties of a cell-free system for bacteriophage t4 late rna synthesis. | a cell-free system for synthesizing bacteriophage t4 late rna is described. the system, which is based on the "cellophane disc" technique introduced by schaller and co-workers (schaller, h., otto, b., nüsslein, v., huf, j., hermann, r., and bonnhoeffer, f. (1972) j. mol. biol. 63, 183-200), provides favorable conditions for t4 dna and rna synthesis in vitro. total rna synthesis can be sustained for more than 1 h at 25 degrees c and initiation of early and late rna chains occurs in vitro. the cap ... | 1979 | 368054 |
| an escherichia coli ribonuclease which removes an extra nucleotide from a biosynthetic intermediate of bacteriophage t4 proline transfer rna. | the biosynthesis of bacteriophage t4 trnapro, trnaser, and trnaile requires enzymatic removal of extra nucleotides from the 3' terminus of the respective precursor rnas. a ribonuclease activity capable of catalyzing such reactions has been partially purified from uninfected escherichia coli using an artificial precursor rna as substrate. a number of ribonuclease activities were resolved during purification. use of e. coli strain bn, a mutant known to be deficient in the relevant ribonuclease act ... | 1978 | 364422 |
| model for dna packaging into bacteriophage t4 heads. | the mechanism of dna packaging into bacteriophage t4 heads in vivo was investigated by glucosylation of hydroxymethylcytosine residues in a conditionally glucose-deficient host. cytoplasmic dna associated with partially packaged ts49 heads can be fully glucosylated, whereas dna already packaged into these heads is shown to be resistant to glucosylation. after temperature shift and completion of arrested packaging into the reversible temperature-sensitive ts49 head, the structure of the dna in th ... | 1978 | 364076 |
| role of lipopolysaccharide and outer membrane protein of escherichia coli k-12 in the receptor activity for bacteriophage t4. | lipopolysaccharide isolated from escherichia coli k-12 did not inactivate phage t4, although the cell envelopes with 1% sodium deoxycholate resulted in the release of cytoplasmic membrane proteins, 70% of the lipopolysaccharide, and almost all of the phospholipid. the reconstitution of phage receptor activity was achieved from deoxycholate-soluble and -insoluble fractions by dialysis against a solution of magnesium chloride. lipopolysaccharide was the only essential component in the deoxycholate ... | 1978 | 361717 |
| glutathione-dependent enzyme reactions of the phage t4 ribonucleotide reductase system. | 1978 | 359548 | |
| ionic strength perturbation kinetics of gene 32 protein dissociation from its complex with single-stranded dna. | equilibrium and kinetic studies of the interaction of gene 32 protein of t4 phage with single-stranded fd dna were performed monitoring the changes in protein fluorescence. from the fluorescence titrations, it was estimated that a monomer of gene 32 protein covered six nucleotide bases on the dna and the lower limit for the apparent association constant was 1.9 x 10(8) m-1 with a cooperative parameter of 10(3) in 0.1 m 2-amino-2-hydroxymethyl-1,3-propanediol hydrochloride (ph 7) at 25 degrees c. ... | 1978 | 359047 |
| further characterization of the r plasmid rts1 and its mutant ptw2: replication and incompatibility of the plasmid. | incompatibility of the r plasmid rts1 and its replication mutant ptw2 was studied in reca host cells of escherichia coli. when the r plasmid r401, belonging to the same incompatibility group as rts1, was used as a test plasmid, r401 was eliminated preferentially from (rts-r401)+ cells irrespective of the direction of transfer. in contrast, ptw2 and r401 were mutually excluded. the decreased incompatibility of ptw2 was confirmed by a direct incompatibility test in which a derivative of rts1 expel ... | 1978 | 355218 |
| selectivity of rna chain initiation in vitro. 1. analysis of rna initiations by two-dimensional thin-layer chromatography of 5'-triphosphate-labeled oligonucleotides. | a method for the rapid and quantitative analysis of 5'-terminal oligonucleotides of rnas made in vitro is described. the method involves synthesis of rna in the presence of [gamma-32p]atp or gtp, isolation of the rna, and digestion with t1 or pancreatic ribonucleases to release labeled 5'-triphosphate termanated oligonucleotides. the oligonucleotides are then subjected to chromatography on a polyethyleniminecellulose thin-layer system using 2 m licl, 0.01 m edta (ph 6.5) in the first dimension a ... | 1978 | 352390 |
| genetic and physiological characterization of escherichia coli k12 mutants (tabc) which induce the abortive infection of bacteriophage t4. | 1978 | 351929 | |
| functional compartmentation of dna precursors in t4 phage-infected bacteria. | 1978 | 348692 | |
| construction and properties of recombinant plasmids containing the rii genes of bacteriophage t4. | the ecori digestion products of phage t4 dna have been examined using a phage dna transformation assay. a 2.6 x 10(6) dalton fragment was found to contain the rii genes. this fragment was purified and then treated with hindiii endonuclease. the cleavage products were ligated to the vector plasmid pbr313 and viable recombinant plasmids recovered. a genetic assay was employed to demonstrate that the recombinants contained t4 dna and to localize on the phage genetic map the ecori and hindiii sites ... | 1978 | 345100 |
| attachment of tail fibers in bacteriophage t4 assembly. purification, properties, and site of action of the accessory protein coded by gene 63. | 1978 | 344316 | |
| stimulation of cell division by t4 infection in escherichia coli dnaets at nonpermissive temperature. | filamentous cells resulting from growth of a dnaets mutant of escherichia coli at high temperature were stimulated to divide by infection with bacteriophage t4. the effect appears to be related to t4 dna synthesis; no increase in cell number took place in chloramphenicol-treated. t4-infected cells nor in cells infected with dna synthesis-less mutants of t4. the ability of cells to divide after t4 infection was dependent on the length of time that the cells had been grown at 42 degrees c, indicat ... | 1977 | 337113 |
| t4 phage-coded deoxycytidylate hydroxymethylase: purification and studies on intermolecular interactions. | 1977 | 332172 | |
| bacteriophage t4 virion dihydrofolate reductase: approaches to quantitation and assessment of function. | this paper is concerned with the physiological role(s) of t4 phage-coded dihydrofolate reductase, which functions both in dna precursor metabolism and as a virion protein. (i) we have detected enzyme activity in noninfectious particles produced under restrictive conditions by gene 11 mutants. this supports the conclusion of kozloff et al. (j. virol. 16:1401-1408, 1975) that the protein lies in the baseplate, covered by the gene 11 protein. (ii) we have obtained further evidence for virion dihydr ... | 1977 | 330880 |
| further studies on bacteriophage t4 dna synthesis in sucrose-plasmolyzed cells. | this paper describes several technical improvements in the sucrose-plasmolyzed cell system used in earlier experiments on dna synthesis in situ with escherichia coli infected by dna-defective mutants of bacteriophage t4 (w. l. collinsworth and c. k. mathews, j. virol. 13:908-915, 1974). using this system, which is based primarily on that of m. g. wovcha et al. (proc. natl. acad. sci. u.s.a. 70:2196-2200, 1973), we reinvestigated the properties of mutants bearing lesions in genes 1, 41, and 62, a ... | 1977 | 328926 |
| proteolysis during t4 head maturation: evidence against the involvement of a phage-induced trypsin-like enzyme. | 1977 | 327685 | |
| regulation of the expression of bacteriophage t4 genes 32 and 43. | 1977 | 324117 | |
| isolation and characterization of conditional-lethal rho mutants of escherichia coli. | temperature-sensitive nita (rho) mutants of e. coli were isolated; one of them was characterized as an amber mutant. these strains show the nit phenotype (transcription of phage lambda dna independent of the n gene) at low temperatures and are inviable at high temperatures. the mutated sites appear to be between cya and mete on the chromosome. temperature-sensitive nita bacteria not only permit leftward transcription of the lambda genome at a high rate in the absence of the lambda n protein, but ... | 1977 | 322147 |
| mutants of escherichia coli "cryptic" for certain periplasmic enzymes: evidence for an alteration of the outer membrane. | mutants in which the expression of periplasmic enzymes by whole cells is reduced (termed "cryptic") are also found to show greatly reduced uptake of labeled adenosine 5'-monophosphate (5'-amp), providing a rapid assay for crypticity. the crypticity of 3'- and 5'-nucleotidase has been examined as a function of substrate concentration. the km for 3'- or 5'-amp increases in the cryptic mutants when whole cells are used as the enzyme source. the vmax is not altered. electrophoretic analysis of prote ... | 1977 | 320175 |
| phage t4-modified rna polymerase transcribes t4 late genes in vitro. | initiation of t4 late rna synthesis has been achieved in an in vitro system prepared from escherichia coli cells infected with wild-type or maturation-defective mutant t4 phage. the system uses a cellophane membrane as a mechanical support for concentrated cell lysates and for added streptolydigin-resistant rna polymerases. transcriptional activity and selectivity of added rna polymerases are tested while endogenous rna polymerase activity is inhibited by streptolydigin. t4-modified rna polymera ... | 1977 | 271954 |
| excision of bromodeoxyuridine from t4-dna by an antimutator polymerase of t4 phage. | with gene-43 (dna polymerase)-ts-mutants of t4 phage, l98 (mutator) and cb121 (antimutator), and the t4 wild type, double labelling of dna was carried out with (h3)-bromodeoxyuridine (budr) and (c14)-thymidine (tdr). experiments on (c14) tdr for dna synthesis measurement in the presence of budr offered evidence of the ability of the cb121 mutant to excise budr from the dna. this effect took place only at increased temperature. as distinct from dna synthesis of the host, all t4 phages used prefer ... | 1975 | 239571 |
| a new system for studying molecular mechanisms of mutation by carcinogens. | a new system for studying the molecular mechanisms of mutation by carcinogens is described. the system involves (a) site-specific modification of the essential gene g in phi x174 replicative form dna by a combination of chemical and enzymatic steps; (b) production of mutant virus carrying a change at a single preselected site by transfection of spheroplasts with the site modified phi x174 dna; (c) detection and propagation of mutants using a host carrying the plasmid, p phi xg, that rescues all ... | 1979 | 227905 |
| the purification of nuclease-free t4-rna ligase. | rna ligase has been highly purified in good yields from bacteriophage t4-infected escherichia coli by a rapid and reproducible procedure. the enzyme is free of phosphomonoesterase and ribonuclease activities and is therefore suitable for the synthesis of oligoribonucleotides and for the labeling of the 3'-terminus of rna. greater than 90% of the protein in the enzyme preparation migrates as a single band on gradient polyacrylamide gels containing sodium dodecyl sulfate during electrophoresis. fo ... | 1979 | 219895 |