unbiased participation of t4 phage dna strands in replication. 19694890822
enzymatic activities on cell walls in bacteriophage t4. 19694891420
site- and gene-specific limited heterocatalytic expression in bacteriophage t4-infected escherichia coli.genetic evidence for site- and gene-specific variation in limited heterocatalytic expression in phage t4-infected escherichia coli is reported, and the implications of such variation are discussed.19694891752
intermediates in t4 dna replication in a t4 ligase deficient strain. 19684891959
phage dna synthesis in bacteria infected with t4 light particles. 19684891977
dna polymerase and the cell membrane after t4 infection. 19684891988
studies of deoxycytidylate deaminase from t4-infected escherichia coli. 19694893683
[synthesis of early phage messengers in escherichia coli infected by t4 during a specific amino acid deficiency]. 19694894287
dna-dependent synthesis of rna by escherichia coli rna polymerase: release and reinitiation of rna chains from dna templates.rna synthesis in an in vitro rna polymerase system at low ionic strength soon ceases, due to inhibition by accumulated rna. measurement of rna chain initiation by the incorporation of gamma-(32)p-atp and gtp with native t2 or t4 dna as template shows that only one rna chain is formed per molecule of enzyme added. in contrast, when the polymerase reaction is carried out in 10 mm mg(++) and 0.2 m kcl, rna synthesis proceeds nearly linearly for hours, resulting in a marked increase in accumulated r ...19694901708
mutagenic effect of sensitized irradiation of bacteriophage t4. 19694902206
enzymic joining of polynucleotides. 8. structure of hybrids of parental t4 dna molecules. 19694904104
selective translation of t4 template rna by ribosomes from t4-infected escherichia coli.the present studies indicate that t4 infection induces an alteration in host ribosomes which restricts the translation of host and other t4-unrelated template rnas but permits normal translation of t4 rna. a heat-labile factor has been isolated from t4-infected cell ribosomes which, when combined with normal cell ribosomes, confers upon the latter the property of selective t4 template rna translation.19694904642
transcription specificity of e. coli and t4 rna polymerase. 19694906604
transcription of the bacteriophage t4 template. obligate synthesis of t4 prereplicative rna in vitro. 19704907328
intergenic suppression of amber polynucleotide ligase mutation in bacteriophage t4. 19704909415
in vitro synthesis of t4 proteins: lysozyme and the products of genes 22 and 57. 19694909532
terminal cross-linking of dna strands by an enzyme system from escherichia coli infected with bacteriophage enzyme system, purified 560-fold from escherichia coli infected with bacteriophage t4, catalyzes the formation of a phosphodiester bond between the original 5'-phosphoryl end-group of a dna strand and a 3'-hydroxyl group of the complementary strand. the product, a terminally cross-linked, spontaneously renaturable dna duplex, has been characterized by chromatographic analysis, by sedimentation analysis, and by enzymatic digestion. essential components of the enzyme system, which requires both ...19704910852
isolation of double-stranded rna from t4 phage infected cells. 19704911222
suppression of adsorption properties of a z mutant of bacteriophage t4 by r mutations.the products of bacteriophage t4 r genes influence the organization of the phage-adsorption apparatus in a noncatalytic way.19704911703
control of lysis of t4-infected escherichia coli.the lysis of escherichia coli b/5 infected with t4dr48 could be delayed by addition of 9-aminoacridine (9aa). infected cells showed an early period of maximal response followed by a decline in sensitivity. the ultimate rate of lysis was also affected by the dye. deoxyribonucleic acid (dna), protein, and lysozyme synthesis began at the normal time in complexes inhibited by 9aa addition. the rates of synthesis of these macromolecules were lower in the presence of the dye, with dna and lysozyme syn ...19684911852
growth of a dihydrofolate reductaseless mutant of bacteriophage t4.a mutant of bacteriophage t4 was isolated which was unable to induce virus-specific dihydrofolate reductase in infected cells. the mutant was able to form several other early enzymes of pyrimidine metabolism. growth of the mutant in a wild-type host, escherichia coli b, was compared with that of the parent strain, t4bo(1), and t4td8, a mutant which lacks the ability to induce thymidylate synthetase. growth studies were carried out in minimal medium, which gave higher growth rates and phage yield ...19674912241
molecular recombination in t4 bacteriophage deoxyribonucleic acid. ii. single-strand breaks and exposure of uncomplemented areas as a prerequisite for recombination.deoxyribonucleic acid (dna) from several "dna-deficient" amber mutants was observed to be either nicked (amber 22, 82, 122, and wild type) or cut (amber 453) after injection into a nonpermissive host. this effect was inhibited by chloramphenicol (cm), indicating that it is due to phage-induced enzymes. although most of the mutants tested for replication in a density-label system were in fact dna-deficient (amber 22, 82, 122), one (amber 81) was found to replicate almost identically to the wild t ...19674912244
initiation and release of rna by dna-dependent rna polymerase.during in vitro transcription of t4 dna by e. coli rna polymerase, chain initiation stops coincidentally with synthesis at low ionic strength (0.11) with an average of one rna chain initiated per 24s polymerase molecule. at high ionic strength (0.37), initiation as well as synthesis continues for several hours, with an average of four chains initiated per enzyme molecule in two hours. the rna product is released from the t4 dna template at both low and high ionic strength. at high ionic strength ...19704913208
double-strand scissions in bacteriophage t4 deoxyribonucleic acid as a result of 32p decay.double-strand scissions produced by decay of (32)p incorporated into t4 deoxyribonucleic acid (dna) were detected in cross-linked dna and dna containing (32)p in only one strand of the double helix.19704916325
possible function of rii genes of bacteriophage t4. 19704919868
analysis of t4 phage proteins. i. conversion of precursor proteins into lower molecular weight peptides during normal capsid formation.radioisotopically labeled t4-proteins extracted from purified capsids and phage and from infected cells were separated by gel electrophoresis in the presence of sodium dodecyl sulfate and a reducing reagent. they were identified by autoradiography and by counting of the fractionated gels. four major protein bands (f, a, d, and e) were detected in capsid and phage. these accounted for more than 90% of the total capsid protein and 70% of the phage protein (60% of the total capsid protein was in a- ...19704920094
[absence of a requirement for tryptophan in the bactericidal action of t4 phage ghosts]. 19694920134
unbiased synthesis of pulse-labeled dna framents of bacteriophage lambda and t4. 19704922215
on the fidelity of phage t4-induced polynucleotide ligase in the joining of chemically synthesized deoxyribooligonucleotides. 19704923217
control of synthesis of glucosyl transferase and lysozyme messengers after t4 infection. 19704923861
a preferred origin and direction of bacteriophage t4 dna replication. i. a gradient of allele frequencies in crosses between normal and small t4 particles. 19704924010
continuous requirement for host p10 protein during bacteriophage t4 infection.the escherichia coli 30s ribosomal protein p10, the product of the str gene, known to be involved only in the initiation of protein syntehsis, is required for all bacteriophage t4 protein synthesis.19704925776
repair of alkylated bacteriophage t4 deoxyribonucleic acid by a mechanism involving polynucleotide ligase.methyl methanesulfate-induced lesions in bacteriophage t4 are repaired primarily by a mechanism involving polynucleotide ligase. apparently, other recombinational and ultraviolet repair functions aren't involved.19714927528
dark repair of ultraviolet-irradiated deoxyribonucleic acid by bacteriophage t4: purification and characterization of a dimer-specific phage-induced endonuclease.the purification and properties of an ultraviolet (uv) repair endonuclease are described. the enzyme is induced by infection of cells of escherichia coli with phage t4 and is missing from extracts of cells infected with the uv-sensitive and excision-defective mutant t4v(1). the enzyme attacks uv-irradiated deoxyribonucleic acid (dna) containing either hydroxymethylcytosine or cytosine, but does not affect native dna. the specific substrate in uv-irradiated dna appears to be pyrimidine dimer site ...19714929862
synthesis of ribonucleic acid and protein in plasmid-containing minicells of escherichia coli k-12.unlike the deoxyribonucleic acid (dna)-deficient minicells produced by f(-) parents, minicells produced by plasmid-containing strains contain significant amounts of plasmid dna. we examined the ability of plasmid-containing minicells to synthesize ribonucleic acid (rna) and protein. in vivo, minicells produced by f(-) parents are unable to incorporate radioactive precursors into acid-insoluble rna or protein, whereas minicells produced by f', r(+), or col(+) parents are capable of such synthesis ...19714935321
t4 bacteriophage-specific dihydrofolate reductase: purification to homogeneity by affinity chromatography. 19714936128
specific cleavage of an escherichia coli leucine transfer rna following bacteriophage t4 infection. 19714937193
genetic distances separating adjacent base pairs in bacteriophage t4. 19714937995
chain growth rate of messenger rna in escherichia coli infected with bacteriophage t4. 19684938556
properties of bacteriophage t4 mutants defective in gene 30 (deoxyribonucleic acid ligase) and the rii escherichia coli k-12 strains infected with phage t4 which is defective in gene 30 [deoxyribonucleic acid (dna) ligase] and in the rii gene (product unknown), near normal levels of dna and viable phage were produced. growth of such t4 ligase-rii double mutants was less efficient in e. coli b strains which show the "rapidlysis" phenotype of rii mutations. in pulse-chase experiments coupled with temperature shifts and with inhibition of dna synthesis, it was observed that dna synthesized by gen ...19714939059
partial suppression of bacteriophage t4 ligase mutations by t4 endonuclease ii deficiency: role of host ligase.endonuclease ii-deficient, ligase-deficient double mutants of phage t4 induce considerably more deoxyribonucleic acid (dna) synthesis after infection of escherichia coli b than does the ligase-deficient single mutant. furthermore, the double mutant can replicate 10 to 15% as well as wild-type t4, whereas the single mutant fails to replicate. when the e. coli host is also deficient in ligase, the double mutant resembles the single mutant. the results indicate that host ligase can substitute for p ...19714939389
an in vitro transversion by a mutationally altered t4-induced dna polymerase. 19684939629
role of gene 46 in bacteriophage t4 deoxyribonucleic acid an attempt to establish whether escherichia coli b infected with n130 (an amber mutant defective in gene 46) is recombination-deficient, the postinfection fate of (14)c-labeled n130 parental deoxyribonucleic acid (dna) was followed, its amount in complex with the host cell membrane being determined in sucrose gradients after mild lysis of the infected cells. the parental dna was found to undergo gradual detachment from the membrane during infection. pulse-chase experiments similarly showed th ...19714940242
suppression of temperature sensitive mutants of bacteriophage t4 by bacterial opal suppressors. 19714940425
bacteriophage t4 inhibits colicin e2-induced degradation of escherichia coli deoxyribonucleic acid. i. protein synthesis-dependent inhibition.the deoxyribonucleic acid (dna) of escherichia coli b is converted by colicin e2 to products soluble in cold trichloroacetic acid; we show that this dna degradation (hereafter termed solubilization) is subject to inhibition by infection with bacteriophage t4. at least two modes of inhibition may be differentiated on the basis of their sensitivity to chloramphenicol. the following observations on the inhibition of e2 by phage t4 in the absence of chloramphenicol are described: (i) simultaneous ad ...19714940930
structure of the dna ligase-adenylate intermediate: lysine (epsilon-amino)-linked adenosine monophosphoramidate.proteolytic degradation of the escherichia coli dna ligase-adenylate intermediate releases adenosine 5'-monophosphate linked to the epsilon-amino group of lysine by a phosphoamide bond. measurements of the rate of hydroxylaminolysis of the ligase-adenylate provide further support for a phosphoamide linkage in the native enzyme. lysine (epsilon-amino)-linked adenosine monophosphoramidate has also been isolated from the t4 phage-induced ligase-adenylate intermediate. these results indicate that an ...19714944632
phospholipid hydrolysis before the onset of lysis in t4-infected escherichia coli. 19714944865
resistance of escherichia coli to penicillins. ix. genetics and physiology of class ii ampicillin-resistant mutants that are galactose negative or sensitive to bacteriophage c21, or both.ampicillin-resistant mutants of class ii are determined by a doubling of chromosomally and episomally mediated ampicillin resistance on agar plates. several mutants were isolated from a female as well as from an hfr strain. the mutants differed from each other in various properties such as response to colicin e2 and sodium cholate, response to the phages t4 and c21, and fermentation of galactose. by conjugation and transduction experiments, it was shown that mutations in at least four loci gave ...19714945191
a reduced activity of a deoxyribonuclease requiring atp in escherichia coli infected by bacteriophage t4. 19714946708
interruption of the phage t4 chromosome transfer into the cell. cyclic permutations of genes, and infective activity of the fragmented genome. 19714949478
localization of parental deoxyribonucleic acid from superinfecting t4 bacteriophage in escherichia coli.high-resolution autoradiography has been employed to localize the nonsolubilized but genetically excluded deoxyribonucleic acid (dna) of t4 bacteriophage superinfecting endonuclease i-deficient escherichia coli. this dna was found to be associated with the cell envelope (this term is used here to include all cellular components peripheral to and including the cytoplasmic membrane); in contrast, t4 dna in primary infected cells, like host dna in uninfected e. coli, was found to be near the cell c ...19714950703
[attachment of lambda and t4 phage deoxyribonucleic acids to an escherichia coli membrane particle fraction and functions of the complex in transcription of dna to specific messenger rna]. 19694979265
resistance of escherichia coli to penicillins. 8. physiology of a class ii ampicillin-resistant mutant.class ii ampicillin-resistant mutants of escherichia coli are defined as having a twofold increase in penicillinase-mediated ampicillin resistance when determined by colony formation tests on plates. in this paper, one class ii mutant has been compared to its parent strain. in liquid medium, the mutant was less resistant than the parent strain both in the absence and in the presence of r1 and r-factor mediating penicillinase activity. the penicillinase activity was found to be almost completely ...19704985589
template properties of complementary fractions of denatured microbial deoxyribonucleic acids.dna preparations from seven bacterial species and from e. coli phage t4, and also the complementary l and h fractions into which these dna specimens, after denaturation, were separated by chromatography on methylated albumin-kieselguhr columns, were studied as templates in the rna polymerase system, and the nucleotide composition of the rna products was determined. the rna transcripts of the separated l and h fractions were found to be faithful copies of the respective dna fractions. this sugges ...19704985881
early intracellular events in the replication of t4 bacteriophage deoxyribonucleic acid. vii. 32p suicide stabilization.the relationship between (32)p suicide stabilization and deoxyribonucleic acid (dna) replication during infection of escherichia coli by bacteriophage t4 was reinvestigated. replication of the parental phage dna was detected at early stages of stabilization.19704989103
reversal of restriction for host modified t2 and t4 dna upon conversion of non-permissive escherichia coli to spheroplasts. 19655319592
gene-specific messenger rna: isolation by the deletion method.messenger rna molecules, homologous to a small portion of the genome of bacteriophage t4, have been isolated. rna fragments specific to the rii a and the rii b cistrons have been separated by hybridization with dna isolated from appropriate deletion mutants. an rna species homologous in nucleotide sequence to a defined part of the rii a cistron has been identified.19665323418
the synthesis of deoxycytidylate deaminase and dihydrofolate reductase and its control in escherichia coli infected with bacteriophage t4 and t-4 amber mutants. 19665327746
the infection of escherichia coli by t2 and t4 bacteriophages as seen in the electron microscope. ii. structure and function of the baseplate. 19675337969
limited genome expression in bacteriophage t4-infected escherichia coli. i. demonstration of the effect. 19665339599
characteristics of mutations appearing spontaneously in extracellular particles of bacteriophage t4. 19675341474
hycanthone: a frameshift mutagen.rapid spot-test screening of antischistosomal agents reveals that hycanthone is a potent frameshift mutagen while the closely related compound, miracil d, is nonmutagenic in salmonella. both hycanthone and miracil d are frameshift mutagens for t4 bacteriophage during growth in escherichia coli.19715573958
effect of prophage w on the propagation of bacteriophages t2 and t4.studies have been undertaken to determine whether the temperate phage omega present in escherichia coli strain w is responsible for the inability of this strain to act as a host for t2 and t4. e. coli ws, cured of phage omega, was sensitive to t2 and t4. lysogenation of e. coli c and ws with phage omega resulted in loss of ability to plate t2 and t4. however, e. coli k-12 lysogens still served as hosts for the t -even phage. two of three ws lysogens studied resembled strain w at the biochemical ...19685701827
in vivo stability of bacteriophage t4 messenger ribonucleic acid.cohen, paul s. (st. jude children's research hospital, memphis, tenn.), and herbert l. ennis. in vivo stability of bacteriophage t4 messenger ribonucleic acid. j. bacteriol. 92:1345-1350. 1966.-a mutant of escherichia coli b, defective in its transport and concentration of k(+), synthesizes ribonucleic acid (rna) without the simultaneous synthesis of protein when depleted of this cation. the mutant was used to study the in vivo stability of phage t4 messenger rna (mrna) in the presence and absen ...19665924268
pyrimidine dimer induction in e. coli dna by cerenkov emission associated with high energy x-irradiation.the induction of pyrimidine dimers in e. coli dna by secondary ultraviolet light associated with 6 mvp x-rays in the dose range 20-90 gy has been demonstrated using t4 endonuclease v. under the experimental conditions used in these experiments the major component of this secondary u.v. light is cerenkov emission.19846094375
identification, physical map location and sequence of the denv gene from bacteriophage t4.the denv gene from bacteriophage t4, which codes for endonuclease v, a small dna repair enzyme, has been cloned and identified by an approach combining dna sequencing and genetics, independent of the phenotypic effect of the cloned gene. appropriate denv+ and denv- deletion mutants were mapped physically to define precisely a region encompassing the denv gene. this region was sequenced in order to identify a protein-coding sequence of the correct size for the denv gene (400-500 bp). finally, ide ...19846095188
regulation of a new bacteriophage t4 gene, 69, that spans an origin of dna replication.we have determined the dna sequence and transcription patterns in a 3-kb segment (between 15 and 18 kb on the standard phage t4 map) spanning an origin of dna replication. a new gene, 69, spans this origin. gene 69 codes for two overlapping proteins that share a common c-terminal segment. defective dna replication in an appropriate amber mutant shows that at least the larger of the two proteins is required for efficient t4 dna replication. the two proteins coded by gene 69 are expressed from dif ...19846098451
postinfection control in t4 bacteriophage infection: inhibition of the rep function.we suggest that the general mechanism by which t4 phage turns off host macromolecular synthesis involves specific phage proteins which react with key components in the synthetic pathway. support for this mechanism exists for the inhibition of host rna synthesis. here we note that the host rep function was inhibited after t4 phage infection. since rep functions are known to be involved in host dna replication, inhibition of rep might alter the course of host dna replication.19816112279
efficiency of t4 dna ligase-catalyzed end joining after s1 endonuclease treatment on duplex dna containing single-stranded portions.covalently closed-circular, superhelical sv4o dna was used in all experiments. ecori endonuclease- and hpaii endonuclease-generated unit-length linear duplex dnas were digested with s1 endonuclease under the conditions where single-stranded cna was completely converted into the acid-soluble form. these were subjected to an end-to-end joining test with t4 dna ligase. the ligation efficiency was significantly lower than that of the flush-ended linear duplex dnas which were generated by both hpai e ...19816171303
processing of bacteriophage t4 trnas. the role of rnaase iii. 19816175760
isolation, properties and nucleolytic degradation of chromatin from escherichia coli.a new procedure has been developed for the isolation of the chromosome complex, termed chromatin, from escherichia coli. the bacteria were subjected to low ionic strength and t4 lysozyme, followed by detergent treatment analogous to that employed for the isolation of eukaryotic chromosomes. the chromatin was an insoluble viscous material which contained approximately equal amounts of dna and rna. the protein content of the chromatin was almost three times greater than the nucleic acid content. e ...19826190986
initiation site of deoxyribonucleotide polymerization at the replication origin of the escherichia coli chromosome.a new round of chromosomal replication of a temperature-sensitive initiation mutant (dnac) of escherichia coli was initiated synchronously by a temperature shift from a nonpermissive to a permissive condition in the presence of arabinosyl cytosine. increased amounts of nascent dna fragments with homology for the chromosomal segment containing the replication origin (oric) were found. the nascent dna fragments were purified and treated with alkali to hydrolyze putative primer rna and to expose 5' ...19836191181
escherichia coli can lacks a trna-processing nuclease.escherichia coli strain can is unable to support the growth of bacteriophage t4 strains requiring the suppressor function of t4 trnaser. biochemical analysis of the mutant strain revealed that it is deficient in a rnase which acts on the artificial trna precursor trna-c-u.19836194149
self cleavage of a precursor rna from bacteriophage t4.we found that a precursor of an rna molecule from t4-infected escherichia coli cells (p2spl; precursor of species 1) has the capacity to cleave itself in a specific position. this cleavage is similar to a cleavage carried out by the aid of a protein, rnase f, that has been previously identified. this cleavage could lead to the maturation of an rna (species 1) found in t4-infected e. coli cells. the reaction is time and temperature-dependent and is relatively slow as compared to the protein-depen ...19846198526
[effect of freezing modes on the survival of escherichia coli bacteriophages].the object of this work was to study the effect of freezing down to--196 degrees c at different cooling and warming rates on the survival of t3, t4 and phix174 phages. phage particles survived when t3 phage was frozen at a rate of 20-400 degrees/min and phix174 phage at a rate of 20-45 degrees/min. the survival rate of t4 phage was highest when it was frozen at a rate of 45 degrees/min. the survival of the phages depended also on the regime of warming. the susceptibility of the phages to freezin ...19826216396
the generation and analysis of clones containing bacteriophage t4 dna fragments. 19806246245
control of early gene expression of bacteriophage t4: involvement of the host rho factor and the mot gene of the bacteriophage.many early mrna species of bacteriophage t4 are not synthesized after infection of escherichia coli in the presence of chloramphenicol. this has been interpreted as a need for t4 protein(s) to be synthesized to allow expression of some early genes, e.g., those for deoxycytidinetriphosphatase, deoxynucleosidemonophosphate kinase and udp-glucose-dna beta-glucosyltransferase. in the experiments described here, early mrna of bacteriophage t4 was allowed to accumulate during chloramphenicol treatment ...19806251243
studies on phage internal proteins. vi. interaction of bacteriophage t4 internal proteins with t4 dna in vivo and in vitro.internal proteins are basic proteins bound to the dna of t4 coliphage. centrifugation in sucrose gradients was employed to isolate dna-internal proteins complexes formed in vitro. polyacrylamide gel electrophoresis of radioactive internal proteins in the presence of sodium dodecyl sulfate followed by autoradiography of the gels was used to identify the dna-bound proteins and to determine their respective abundance in these complexes as well as in the bacteriophage head. the internal proteins wer ...19806251515
bacteriophage t4-related macromolecular synthesis under restriction of plasmid rts1.rts1 is a plasmid which confers upon the host bacteria the capacity to restrict t4 bacteriophage growth at 32 degrees c but not at 42 degrees c. pulse-labeling of phage-infected cells showed that rts1 restricts the synthesis of t1 dna. despite efficient restriction of t4 phage growth and dna synthesis, infected escherichia coli 20so harboring rts1 synthesized both early and late t4 phage rna. synthesis of early t4 phage rna under restrictive conditions (32 degrees c) was almost equal to that fou ...19806255193
studies on t4-head maturation. 2. substrate specificity of gene-49-controlled endonuclease.the substrate specificity of 49+-enzyme was investigated in vitro. the enzyme showed a marked preference for rapidly sedimenting t4 dna (greater than 1000 s) when helix-destabilizing proteins from escherichia coli or phage t4 were added to the reaction. regular replicative t4 dna (200-s dna) or denatured t4 dna was not cleaved by the enzyme in the presence of these proteins but if they were omitted from the reaction both dnas become good substrates for the enzyme. 200-s dna was cleaved at its na ...19816262078
[biosynthesis of early enzymes induced by bacteriophage t4].the biosynthesis of early enzymes of dna-ligase, rna-ligase, dna-polymerase, polynucleotide kinase, exonuclease a induced by bacteriophage t4amn82 was studied. the maximal activity of dna-ligase was observed at the 60th min after the infection, while that of the other enzymes was revealed at the 90th min and reached 4, 45, 529, 120 and 78 units per mg of protein for dna-ligase, rna-ligase, polynucleotide kinase, dna-polymerase and exonuclease a, respectively. bacteriophage t4amn82 induced the ma ...19816271263
rii cistrons of bacteriophage t4. dna sequence around the intercistronic divide and positions of genetic landmarks. 19816273585
selective inhibition by harmane of the apurinic apyrimidinic endonuclease activity of phage t4-induced uv endonuclease.1-methyl-9h-pyrido-[3,4-b]indole (harmane) inhibits the apurinic/apyrimidinic (ap) endonuclease activity of the uv endonuclease induced by phage t4, whereas it stimulates the pyrimidine dimer-dna glycosylase activity of that enzyme. e. coli endonuclease iv, e. coli endonuclease vi (the ap endonuclease activity associated with e. coli exonuclease iii), and e. coli uracil-dna glycosylase were not inhibited by harmane. human fibroblast ap endonucleases i and ii also were only slightly inhibited. th ...19816273822
characterization of the free radical of mammalian ribonucleotide reductase.mouse fibroblast 3t6 cells, selected for resistance to hydroxyurea, were shown to overproduce protein m2, one of the two nonidentical subunits of mammalian ribonucleotide reductase. packed resistant cells gave an epr signal at 77 k very much resembling the signal given by the tyrosine-free radical of the b2 subunit of escherichia coli ribonucleotide reductase. also, the m2-specific free radical was shown to be located at a tyrosine residue. of the known tyrosine-free radicals of ribonucleotide r ...19826279610
template-prime-dependent turnover of (sp)-datp alpha s by t4 dna polymerase. the stereochemistry of the associated 3' goes to 5'-exonuclease.t4 dna polymerase converts (sp)-2'-deoxyadenosine 5'-o-(1-thio[1-18o2]triphosphate) to 2'-deoxyadenosine 5'-o-[18o]-phosphorothioate in the presence of poly(d(a-t).poly(d(a-t)) template-primer. control experiments involving either omitting the poly(d(a-t)).poly(d(a-t) template-primer or employing the (rp)-2'-deoxyadenosine 5'-o-(1-thiotriphosphate) diastereomer showed no reaction. it is assumed, therefore, that this conversion as in the p--o case involves incorporation of the thionucleotide into ...19826282851
independent locations of kinase and 3'-phosphatase activities on t4 polynucleotide kinase.we have used two chemical modification reagents and three proteases to study the relationship between the two activities of t4 polynucleotide kinase. in each case, conditions were found where one of the two activities of the enzyme could be eliminated without greatly reducing the other. taken together, these data indicate that the two activities are catalyzed by amino acid residues located in separate active sites on the polypeptide chain. specific exopeptidase digestion indicates that the kinas ...19826288680
bacteriophage t4-induced anticodon-loop nuclease detected in a host strain restrictive to rna ligase mutants.the fate of host trnas during t4 bacteriophage infection was investigated with escherichia coli ctr5x, the only known host strain that is restrictive to rna ligase and polynucleotide kinase mutants. three ctr5x trna species were cleaved during infection. one was leucine trna1, which was cleaved in the extra arm, as reported elsewhere for e. coli b infected with bacteriophage t2 or t4. the other two were specific to e. coli ctr5x and were not cleaved in various other hosts. one of the cleaved ctr ...19826296815
limited proteolysis studies on the escherichia coli single-stranded dna binding protein. evidence for a functionally homologous domain in both the escherichia coli and t4 dna binding proteolysis can be used to remove either 42 or 62 amino acids at the cooh terminus of the 18,873-dalton escherichia coli single-stranded dna binding protein (ssb). since poly(dt), but not d(pt)16, increases the rate of this reaction, it appears that cooperative ssb binding to single-stranded dna (ssdna) is associated with a conformational change that increases the exposure of the cooh terminus to proteolysis. as a result of this dna-induced conformational change, we presume that the cooh ...19836298232
studies on dna replication in the bacteriophage t4 in vitro system. 19836305581
site-specific cleavage of bacteriophage t4 dna associated with the absence of gene 46 product function.a plasmid containing a copy of the late gene 23 was cleaved at two specific locations after bacteriophage t4 infection. cleavage at the major site, which is at the 3' end of gene 23, was detected only in the absence of gene 46 product function and was independent of the state of modification of cytosine residues. cutting of plasmid (cytosine-containing) dna at this site was independent of phage dna replication and late transcription functions. a second cleavage site, in vector dna, was also mapp ...19836306283
primary structure and genetic organization of phage t4 dna ligase.the primary structure of phage t4 dna ligase has been determined by dna sequencing of a cloned restriction fragment containing its gene, and partial amino acid sequence analysis of the protein. the molecule has a mr of 55,230, and contains 487 amino acids. the dna sequence may also encode all of one and parts of two other, hitherto unidentified, t4 proteins. the four genes are closely packed, with overlaps between terminator and initiator codons of adjacent genes. potential terminator and promot ...19836314278
mechanism of ribosome frameshifting during translation of the genetic code.some frameshift mutations are strongly suppressed by limitation for particular aminoacyl-trna species. here, we show that ribosome frameshifting at a specific tryptophan codon during trp-trna limitation accounts for suppression of a group of downstream frameshift alleles in the riib gene of bacteriophage t4. genetic and physiological observations strongly suggest that ribosome frameshifting at this position depends on the binding of a noncognate (leucine) trna.19836339944
stabilization of proteins by a bacteriophage t4 gene cloned in escherichia coli.the cloned bacteriophage t4 pin gene functions to stabilize several different kinds of proteins in escherichia coli bacteria. incomplete proteins such as puromycyl polypeptides, abnormal but complete proteins such as the lambda phage tso protein, and labile eukaryotic proteins encoded by genes cloned in e. coli such as mature human fibroblast interferon are stabilized in cells in which the t4 pin gene is expressed. the cloned t4 pin gene does not seem to affect the turnover of normal e. coli pro ...19836340113
ribonuclease bn: identification and partial characterization of a new trna processing enzyme.a new ribonuclease, rnase bn, has been identified and partially purified from a strain of escherichia coli lacking rnase ii and rnase d by using the artificial trna precursor trna-c-[14c]u as substrate. this enzyme is present in e. coli b but absent from the trna processing mutant strain bn which is unable to process extraneous 3' residues on certain phage t4-specified trna precursors. the properties of rnase bn clearly distinguish this enzyme from other known e. coli exoribonucleases. it is opt ...19836344080
circular permutation analysis of phage t4 dna by electron microscopy.phage t4 is known to have a linear duplex chromosome that is circularly permuted and terminally repeated. we found, by denaturation and self-reannealing experiments, that circular permutation in t4 native dna is not random. their multimodal distribution of permutation is compatible with the "headful packaging" model with the additional specifications that the encapsulation of dna starts at several sites and these are not random distributed.19836346725
r plasmid dihydrofolate reductase with a dimeric subunit structure.dihydrofolate reductase specified by plasmid r483 from a trimethoprim-resistant strain of escherichia coli has been purified 2,000-fold to homogeneity using dye-ligand chromatography, gel filtration, and polyacrylamide gel electrophoresis. the protein migrated as a single band on nondenaturing polyacrylamide gel electrophoresis and had a specific activity of 250 mumol/mg min(-1). the molecular weight was estimated to be 32,000 by gel filtration and 39,000 by ferguson analysis of polyacrylamide g ...19836350298
incorporation of thymine-containing dna precursors in plasmolysed cells infected by the t4 non-lethal recombination defective mutants.incorporation of tdr is aberrant in cells plasmolysed 15 min after infection by the recombination defective t4 chi and omega mutants. the in situ results parallel those obtained in vivo: at high tdr concentrations both t4 chi and t4 omega induced incorporation is slightly reduced compared to wild type, whereas at low tdr concentration incorporation induced by t4 chi is reduced and that induced by t4 omega is increased compared to wild type. no differences between wild type and mutant induced tdr ...19836355762
incorporation of 1,n6-ethenoadenosine into the 3' terminus of trna using t4 rna ligase. 2. preparation and ribosome interaction of fluorescent escherichia coli trnametf.a fluorescent derivative of trnametf from escherichia coli has been prepared which contains 1,n6-etheno-adenosine (epsilon a) in the place of adenosine 73, the fourth residue from the 3' end. the labeled trna, trnametf epsilon a73, is fully active with respect to aminoacylation, formylation and formylmethionyl transfer to puromycin. the preparation procedure entails the chemical removal of four nucleotides from the 3' end of trnametf, ligation of the truncated molecule with epsilon a 3',5'-bisph ...19846363067
effect of temperature on transition and transversion mutagenesis: characterization of wild type and a mutator t4 dna polymerase mutant.the effect of temperature on genetically well-defined mutational pathways was examined in the bacteriophage t4. the mutational site was a t4 rii ochre mutant which could revert to rii+ via a transversion or to the amber convertant via a transition. temperature did not strongly affect any of the pathways examined in a wild-type background; however, increased temperature reduced the mutational activity of a mutator dna polymerase mutant. possible models to explain the role of temperature in mutage ...19846375839
heterogeneity of mammalian dna ligase detected on activity and dna sequencing gels.a new method to detect dna ligase activity in situ after nadodso4 polyacrylamide gel electrophoresis has been developed. after renaturation of active polypeptides the ligase reaction occurs in situ by incubating the intact gel in the presence of mg++ and atp. further treatment with alkaline phosphatase removes the unligated 5'-32p-end of oligo (dt) used as a substrate and active polypeptides having ligase activity are identified by autoradiography. analysis on dna sequencing gels of the oligo (d ...19846377238
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