the fate of phage lambda dna in lambda-infected minicells.the fate of phage lambda dna in lambda-infected escherichia coli minicells harboring the plasmid cole1, and in plasmid-free minicells, were studied. binding of lambda dna to the minicell membrane, and formation of the supercoiled covalently-closed circular structure has been demonstrated. phage infection abolishes plasmid dna synthesis. only a very slight, non-replicative lambda dna synthesis occurs, soon after infection. this synthesis is associated with fragments of lambda dna arising during, ...1979161175
genes for the hook-basal body proteins of the flagellar apparatus in escherichia coli.of the more than 30 genes required for flagellar function, 6 are located between pyrc and ptsg on the escherichia coli genetic man. this cluster of genes is called flagellar region i. four-point transductional crosses were used to establish the position and order of the region i flagellar genes with respect to the outside markers ptsg and pyrc. bacteriophage lambda-e. coli hybrids that contained most of the genes necessary for flagellar formation were constructed. the properties of specific hybr ...1978350831
the structure of a transcriptional unit on colicin e1 an rna-synthesizing system in vitro, a low-molecular-weight rna consisting of about 110 residues (rna-i) was efficiently synthesized on dna of colicin e 1 plasmid (cole1) and its deletion derivatives. the promoter site for rna-i was analysed by testing the rna polymerase-binding ability and template activity of restriction fragments; it was mapped in the region between the replication initiation site and the colicin immunity gene of cole1. the direction of transcription was determined by hybr ...1979380993
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 ...19751102545
unidirectional replication of plasmid cole1 dna. 19744610399
regulatory regions of cole1 that are involved in determination of plasmid copy number.the copy number of plasmid cole1 has been known to increase when the hae ii-c segment downstream from the replication origin is deleted. the presence of the 306-base-pair (bp) hpa ii region in the segment is sufficient for reduction of the copy number. plasmids harboring the region express a trans-acting function that is responsible for the copy number reduction and synthesize a unique protein. a protein specified by the region is purified to near homogeneity and identified as the 63-amino-acid ...19836304700
expression of a dna strand initiation sequence of cole1 plasmid in a single-stranded dna 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
requirements for mobilization of plasmids rsf1010 and cole1 by the incw plasmid r388: trwb and rp4 trag are interchangeable.mobilization of plasmid rsf1010 by the incw plasmid r388 requires the genes involved in w pilus synthesis plus trwb. trag of the incp plasmid rp4 can substitute for trwb in rsf1010 mobilization by r388 but not in self-transfer of r388. this result suggests a dual specificity of trwb-like proteins in conjugation. the same genetic requirements were found for r388 to mobilize the unrelated plasmid cole1.19948021231
peptidase activity of escherichia coli aminopeptidase a is not required for its role in xer site-specific recombination.xer site-specific recombination is required for the stable inheritance of multicopy plasmids and the normal segregation of the bacterial chromosome in escherichia coli. two related recombinases and two accessory proteins are essential for xer-mediated recombination at cer, a recombination site in the plasmid cole1. the accessory proteins, argr and pepa, function in ensuring that the xer recombination reaction acts exclusively intramolecularly, converting plasmid dimers into monomers and not vice ...19948057849
accessory proteins impose site selectivity during cole1 dimer resolution.the cer-xer dimer resolution system of plasmid cole1 is highly selective, acting only at sites on the same molecule and in direct repeat. recombination requires the xercd recombinase and accessory proteins argr and pepa. the escherichia coli chromosome dimer resolution site dif and the type ii hybrid site use the same recombinase but are independent of argr and pepa and show no site selectivity. this has led to the proposal that argr and pepa are responsible for the imposition of constraint. we ...19968736540
selection and characterization of cole1 plasmid mutants that exhibit altered stability and replication.this report describes a method for isolating mutants of plasmid cole1 that exhibit unstable maintenance and altered replication characteristics. it also describes the initial characterization of four mutants isolated by that method. a chimeric plasmid, phsg124, containing a cole1 derivative and a temperature-sensitive replication derivative of psc101 was mutagenized in vitro, using hydroxylamine. by adjusting the growth conditions of transformants containing the mutagenized chimeric deoxyribonuc ...19816268615
characterization of a mini-colc1 in vitro constructed plasmid, pvh15, consisting of the entire genome of the plasmid cole1, the tryptophan operon of escherichia coli, and regions of the bacteriophage phi80pt190, spontaneously gave rise in e. coli to a mini-cole1 plasmid consisting of approximately one-half of the cole1 genome and a small segment of phi80pt190 dna. this mini-cole1 plasmid, designated pvh51, has a molecular weight of approximately 2.1 x 10(6) and possesses a single ecori restriction site. heteroduplex analyses ...1976770430
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 ...1979393952
hypersensitivity to hg2+ and hyperbinding activity associated with cloned fragments of the mercurial resistance operon of plasmid nr1.the region of plasmid nr1 concerned with resistance to hg2+ and organomercurials consists of sequences found on restriction endonuclease fragments ecori-h and ecori-i. when both fragments were cloned together into a derivative of plasmid cole1, the hybrid plasmid conferred properties indistinguishable from those of the parental plasmid, nr1: resistance to hg2+ and to the organomercurials merbromin and fluoresceinmercuric acetate and the inducible synthesis of the enzyme mercuric reductase. when ...1979387720
regulation of the l-arabinose operon in strains of escherichia coli containing cole1-ara hybrid plasmids.hybrid plasmids were constructed from fragments of f'ara episomes formed by the restriction endonuclease ecori and a linear form of the plasmid cole1 created by cleavage with ecori. hybrid plasmids were constructed containing the entire ara region or the ara region with various parts deleted. e. coli k12 host strains were constructed which contained different deletions of the ara region. the hybrid plasmids were transferred to those strains whose ara deletion complemented that of the plasmid. th ...1979384153
cole1 plasmid incompatibility: localization and analysis of mutations affecting incompatibility.deletion mutants of plasmid cole1 that involve the replication origin and adjacent regions of the plasmid have been studied to determine the mechanism by which those mutations affect the expression of plasmid incompatibility. it was observed that (i) a region of cole1 that is involved in the expression of plasmid incompatibility lies between base pairs -185 and -684; (ii) the integrity of at least part of the region of cole1 dna between base pairs -185 and -572 is essential for the expression of ...1979378980
altered dna-protein relaxation complex in a replication mutant of plasmid cole1.approximately 200,000 clones of escherichia coli carrying mutagen-treated colicinogenic plasmid e1 (cole1) were examined for irreversible loss of the plasmid at 43 degrees. thirty of these clones that appeared to be most defective in plasmid dna replication at the non-permissive temperature were selected for the study of: (a) the kinetics of plasmid and chromosomal dna replication during a temperature shift in either the presence or absence of chloramphenicol; (b) the temperature stability of th ...1978368585
cole1 plasmid mutants affecting growth of an escherichia coli recb recc sbcb mutant.three mutant derivatives of the plasmid cole1 were found to reduce the formation of plasmidless cells in a recb recc sbcb cell population. an active plasmid role in the plasmid-host interaction is suggested.1978338596
the heat-shock dnak protein is required for plasmid r1 replication and it is dispensable for plasmid cole1 replication.plasmid r1 replication in vitro is inactive in extracts prepared from a dnak756 strain but is restored to normal levels upon addition of purified dnak protein. replication of r1 in extracts of a dnakwt strain can be specifically inhibited with polyclonal antibodies against dnak. repa-dependent replication of r1 in dnak756 extracts supplemented with dnakwt protein at maximum concentration is partially inhibited by rifampicin and it is severely inhibited at sub-optimal concentrations of dnak prote ...19938265367
site-specific recombination between cole1 cer and ntp16 nmr sites in vivo.the site-specific recombination system used by multicopy plasmids of the cole1 family uses two identical plasmid-encoded recombination sites and four bacterial proteins to catalyze the recombination reaction. in the case of the escherichia coli plasmid cole1, the recombination site, cer, is a 280 bp dna sequence which is acted on by the products of the argr, pepa, xerc and xerd genes. we have constructed a model system to study this recombination system, using tandemly repeated recombination sit ...19957770060
analysis of establishment phase replication of the plasmid cole1.the replication regulatory mechanisms by which the small, multicopy plasmid cole1 maintains a constant steady-state copy number have been extensively characterized by a combination of in vivo genetics and in vitro biochemistry. we have extended the analysis of replication control into the "establishment" phase of replication, when cole1-directed replicons replicate more than once per cell generation and the intracellular concentrations of plasmid-encoded replication regulatory elements are chang ...19937680724
aminoglycoside-modifying enzymes of staphylococcus aureus; expression in escherichia coli.staphylococcus aureus plasmids psh2, rn1956 and pwa1 code for an aminoglycoside phosphotransferase; plasmid pwa1 also encodes an aminoglycoside-aminocyclitol adenylyltransferase. s. aureus plasmid pwa2 confers resistance to erythromycin and sulfonamide. using plasmid cole1-apr (rsf2124) as a vehicle, we have transferred the genes determining aminoglycoside phosphotransferase and aminoglycoside-aminocyclitol adenylyltransferase activities from s. aureus to escherichia coli. the new plasmids obtai ...19806248429
differential scanning calorimetric and theoretical studies of cole1 dna.the differential scanning calorimetry (dsc) of plasmid cole1 dna was carried out. the dsc curve under the solvent condition of 1.0 x ssc buffer gave eleven clear peaks over the temperature range of 83 to 98 degrees c. the dsc curves obtained here were essentially in good agreement with the optical melting curves of cole1 dna reported previously. the theoretical melting profiles of cole1 dna calculated from its entire nucleotide sequence showed a good agreement with the dsc curves. the theoretica ...19863550711
restriction endonuclease ecori alters the enantiomeric preference of chiral metallointercalators for dna: an illustration of a protein-induced dna conformational change.a conformational change in the dna plasmid cole1 appears to occur upon specific binding of the restriction endonuclease ecori. enzyme association alters the chiral discrimination found in binding metallointercalators to dna sites. the complexes tris(1,10-phenanthroline)ruthenium(ii), ru(phen)3(2+), tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(ii), ru(dip)3(2+), and tris(4,7-diphenyl-1,10-phenanthroline)cobalt(iii), co(dip)3(3+), in general, bind stereoselectively to dna helices, with enantiom ...19863011080
determinants of rna hairpin loop-loop complex stability.complexes formed by rna hairpin loops with complementary loop sequences derived from escherichia coli rna i and rna ii, which are involved in the control of dna replication of plasmid cole1, have been analyzed to determine the sequence and structural elements required to achieve full affinity. of particular interest is the origin of the enhanced stability of the complex formed by hairpin loops whose loop sequences have been inverted 5' to 3' with respect to wild-type sequences. full complementar ...19957539081
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