In contrast to recA of other bacteria, the recA gene of Streptomyces lividans has been described as indispensable for viability (G. Muth, D. Frese, A. Kleber, and W. Wohlleben, Mol. Gen. Genet. 255:420-428, 1997.). Therefore, a closer analysis of this gene was performed to detect possible unique features distinguishing the Streptomyces RecA protein from the well-characterized Escherichia coli R...

rnmB281 leads to high constitutive levels of recA protein such that no increase after UV-inducing treatment occurs. The mutation maps in or near the portion of recA corresponding to the NH2-terminal end of the protein. Examination of the recA proteins from rnmB+ recA-/rnmB281 recA+ heterozygotes suggests that both rnmB alleles are cis-acting and codominant. This is the behavior expected from al...

We have developed an affinity column to study the interaction of LexA repressor and other substrates with the activated form of RecA protein. Nucleoprotein complexes of RecA protein, (dT)25-30, and adenosine 5'-[gamma-S]thio-triphosphate were formed in solution and bound to RecA protein-agarose columns. These "activated"-RecA nucleoprotein complexes were retained by strong hydrophobic interacti...

DNA polymerase V (pol V) of Escherichia coli is a translesion DNA polymerase responsible for most of the mutagenesis observed during the SOS response. Pol V is activated by transfer of a RecA subunit from the 3'-proximal end of a RecA nucleoprotein filament to form a functional complex called DNA polymerase V Mutasome (pol V Mut). We identify a RecA surface, defined by residues 112-117, that ei...

The role of ATP hydrolysis in RecA protein-mediated DNA strand exchange reactions remains controversial. Competing models suggest that ATP hydrolysis is coupled either to a simple redistribution of RecA monomers within a filament to repair filament discontinuities, or more directly to rotation of the DNA substrates to drive branch movement unidirectionally. Here, we test key predictions of the ...

Degenerate PCR primers based on conserved RecA protein regions were used to amplify a portion of recA [corrected] from Prevotella ruminicola strain 23, which was used as a probe to isolate the full-length recA gene from the P. ruminicola genomic library. The P. ruminicola recA gene encoded a protein of 340 amino acids with a molecular mass of 36.81 kDa, P. ruminicola RecA was highly similar to ...

The single-stranded DNA binding protein of Escherichia coli (SSB) stimulates recA protein promoted DNA strand exchange reactions by promoting and stabilizing the interaction between recA protein and single-stranded DNA (ssDNA). Utilizing the intrinsic tryptophan fluorescence of SSB, an ATP-dependent interaction has been detected between SSB and recA-ssDNA complexes. This interaction is continuo...

A hallmark of the Escherichia coli SOS response is the large increase in mutations caused by translesion synthesis (TLS). TLS requires DNA polymerase V (UmuD'2C) and RecA. Here, we show that pol V and RecA interact by two distinct mechanisms. First, pol V binds to RecA in the absence of DNA and ATP and second, through its UmuD' subunit, requiring DNA and ATP without ATP hydrolysis. TLS occurs i...

The RecX protein is a potent inhibitor of RecA activities. We identified several factors that affect RecX-RecA interaction. The interaction is enhanced by the RecA C terminus and by significant concentrations of free Mg(2+) ion. The interaction is also enhanced by an N-terminal His(6) tag on the RecX protein. We conclude that RecX protein interacts most effectively with a RecA functional state ...

In Escherichia coli, a relatively low frequency of recombination exchanges (FRE) is predetermined by the activity of RecA protein, as modulated by a complex regulatory program involving both autoregulation and other factors. The RecA protein of Pseudomonas aeruginosa (RecA(Pa)) exhibits a more robust recombinase activity than its E. coli counterpart (RecA(Ec)). Low-level expression of RecA(Pa) ...