CHARACTERIZATION OF 2 STREPTOMYCES-AMBOFACIENS RECA MUTANTS - IDENTIFICATION OF THE RECA PROTEIN BY IMMUNOBLOTTING

The recA gene was isolated from Streptomyces ambofaciens DSM40697. Its nucleotide sequence predicted a protein of 372 residues. Two recA mut ants, NSAR1001 and NSAR57, obtained by gene disruption encoded a RecA protein lacking respectively 30 and at least 62 amino acids from the C -terminal end. NSAR1001 showed a wild-type sensitivity to UV light and oxolinic acid. In contrast, NSAR57 was highly sensitive to these agen ts and the loss of the inserted DNA restored the wild-type phenotype. Western blot analysis using antiserum to Escherichia coli RecA showed that overproduction of RecA was correlated with overtranscription of r ecA in an S. ambofaciens amplified mutant derived from genetic instabi lity.