Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.5.1.2 (DNA ligase)
 2,749 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have examined DNA strand breakage, DNA degradation, and the rate of DNA synthesis in lig and lig-recB strains of Escherichia coli K12 incubated in the presence and absence of 3 mug/ml chloramphenicol. Substantial DNA strand breakage and DNA degradation is observed in the lig strain upon growth at 40 degrees C; however, such strand breakage and DNA degradation is not observed in th lig-recB strainl Incubation of the lig strain at 40 degrees C in the presence of 3 mug/ml chloramphenicol reduces the amount of DNA strand breakage and DNA degradation to the level observed in the lig-recB strain. Together, these results demonstrate that exonuclease V (the recBC gene product) is responsible for the increased DNA degradation associated with DNA ligase deficiency.
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PMID:Effect of chloramphenicol and the recB gene product on DNA metabolism in Escherichia coli K12 strains defective in DNA ligase. 78 29

Homologous recombination is a fundamental biological process. Biochemical understanding of this process is most advanced for Escherichia coli. At least 25 gene products are involved in promoting genetic exchange. At present, this includes the RecA, RecBCD (exonuclease V), RecE (exonuclease VIII), RecF, RecG, RecJ, RecN, RecOR, RecQ, RecT, RuvAB, RuvC, SbcCD, and SSB proteins, as well as DNA polymerase I, DNA gyrase, DNA topoisomerase I, DNA ligase, and DNA helicases. The activities displayed by these enzymes include homologous DNA pairing and strand exchange, helicase, branch migration, Holliday junction binding and cleavage, nuclease, ATPase, topoisomerase, DNA binding, ATP binding, polymerase, and ligase, and, collectively, they define biochemical events that are essential for efficient recombination. In addition to these needed proteins, a cis-acting recombination hot spot known as Chi (chi: 5'-GCTGGTGG-3') plays a crucial regulatory function. The biochemical steps that comprise homologous recombination can be formally divided into four parts: (i) processing of DNA molecules into suitable recombination substrates, (ii) homologous pairing of the DNA partners and the exchange of DNA strands, (iii) extension of the nascent DNA heteroduplex; and (iv) resolution of the resulting crossover structure. This review focuses on the biochemical mechanisms underlying these steps, with particular emphases on the activities of the proteins involved and on the integration of these activities into likely biochemical pathways for recombination.
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PMID:Biochemistry of homologous recombination in Escherichia coli. 796 21