Recombinational DNA repair by the RecF pathway of Escherichia coli requires the coordinated activities of RecA, RecFOR, RecQ, RecJ, and single-strand DNA binding (SSB) proteins. These proteins facilitate formation of homologously paired joint molecules between linear double-stranded (dsDNA) and supercoiled DNA. Repair starts with resection of the b...
Protein-promoted DNA strand exchange requires formation of an active presynaptic complex between the DNA-pairing protein and single-stranded DNA (ssDNA). Formation of such a contiguous filament is stimulated by a ssDNA-binding protein. Here, the effects of replication protein A (RPA) on presynaptic complex formation and DNA strand exchange activiti...
To investigate the in vivo effects of macromolecular crowding we examined the effect of inert macromolecules such as polyvinyl alcohol and polyethylene glycol on the in vitro activity of recA protein. The addition of either of these volume-occupying agents enables recA protein to promote homologous pairing and exchange of DNA strands at an otherwis...
RecBCD is a DNA helicase comprising two motor subunits, RecB and RecD. Recognition of the recombination hotspot, chi, causes RecBCD to pause and reduce translocation speed. To understand this control of translocation, we used single-molecule visualization to compare RecBCD to the RecBCD(K177Q) mutant with a defective RecD motor. RecBCD(K177Q) pause...
The binding and cross-linking of the ATP photoaffinity analogue 8-azidoadenosine 5 -triphosphate (azido-ATP) with recA protein have been investigated, and through cross-linking inhibition studies, the binding of other nucleotide cofactors to recA protein has also been studied. The azido-ATP molecule was shown to be a good ATP analogue with regard t...
In Saccharomyces cerevisiae, the Rad54 protein participates in the recombinational repair of double-strand DNA breaks together with the Rad51, Rad52, Rad55 and Rad57 proteins. In vitro, Rad54 interacts with Rad51 and stimulates DNA strand exchange promoted by Rad51 protein. Rad54 is a SWI2/SNF2-related protein that possesses double-stranded DNA-dep...
We compared the biochemical properties of the RecA441 protein to those of the wild-type RecA protein in an effort to account for the constitutive protease activity observed in recA441 strains. The two RecA proteins have similar properties in the absence of single-stranded DNA binding protein (SSB protein), and the differences that do exist shed lit...
A proteolytic fragment of recA protein, missing about 15% of the protein at the C terminus, was found to promote assimilation of homologous single-stranded DNA into duplex DNA more efficiently than intact recA protein. This difference was not found if Escherichia coli single-stranded DNA binding protein was present. The ATPase activity of both inta...
