Published in Nature
DNA helicases are ubiquitous enzymes that unwind double-stranded DNA. They are a diverse group of proteins that move in a linear fashion along a one-dimensional polymer lattice—DNA—by using a mechanism that couples nucleoside triphosphate hydrolysis to both translocation and double-stranded DNA unwinding to produce separate strands of DNA. The RecB...
Published in Journal of Biological Chemistry
The recA730 mutation results in constitutive SOS and prophage induction. We examined biochemical properties of recA730 protein in an effort to explain the constitutive activity observed in recA730 strains. We find that recA730 protein is more proficient than the wild-type recA protein in the competition with single-stranded DNA binding protein (SSB...
Published in Cold Spring Harbor Perspectives in Biology
Recombinational DNA repair is a universal aspect of DNA metabolism and is essential for genomic integrity. It is a template-directed process that uses a second chromosomal copy (sister, daughter, or homolog) to ensure proper repair of broken chromosomes. The key steps of recombination are conserved from phage through human, and an overview of those...
Published in Molecular Cell
In the October 5 issue of Cell, Singleton et al. report the crystal structure of RecG protein bound to an analog of a stalled DNA replication fork. This structure shows how RecG can recognize branched DNA structures and suggests a mechanism for fork reversal, an early event in recombination-dependent reinitiation of DNA replication.
Published in Journal of Molecular Biology
The AddAB enzyme is important to homologous DNA recombination in Bacillus subtilis, where it is thought to be the functional counterpart of the RecBCD enzyme of Escherichia coli. In vivo, AddAB responds to a specific five-nucleotide sequence (5 -AGCGG-3 or its complement) in a manner analogous to the response of the RecBCD enzyme to interaction wi...
Published in Journal of Molecular Biology
In the accompanying paper, RecA142 protein was found to be completely defective in DNA heteroduplex formation. Here, we show that RecA142 protein not only is defective in this activity but also is inhibitory for certain activities of wild-type RecA protein. Under appropriate conditions, RecA142 protein substantially inhibits the DNA strand exchange...
Published in Journal of Molecular Biology
We have characterized the biochemical properties of Escherichia coli RecA142 protein, the product of a recA allele that is phenotypically defective in genetic recombination. In vitro, this mutant RecA protein is totally defective in DNA heteroduplex formation. Despite this defect, RecA142 protein is not deficient in all other biochemical activities...
Published in Journal of Biological Chemistry
The Saccharomyces cerevisiae Dmc1 and Tid1 proteins are required for the pairing of homologous chromosomes during meiotic recombination. This pairing is the precursor to the formation of crossovers between homologs, an event that is necessary for the accurate segregation of chromosomes. Failure to form crossovers can have serious consequences and m...
Published in Journal of Biological Chemistry
We examined the double-stranded DNA (dsDNA) binding preference of the Saccharomyces cerevisiae Rad52 protein and its homologue, the Rad59 protein. In nuclease protection assays both proteins protected an internal sequence and the dsDNA ends equally well. Similarly, using electrophoretic mobility shift assays, we found the affinity of both Rad52 and...
Published in Proceedings of the National Academy of Sciences
The RecBCD enzyme is important for both restriction of foreign DNA and recombinational DNA repair. Switching enzyme function from the destructive antiviral state to the productive recombinational state is regulated by the recombination hotspot, χ (5 -GCTGGTGG-3 ). Recognition of χ is unique in that it is recognized as a specific sequence within sin...
