Construction of a Streptococcus pyogenes recA mutant via insertional inactivation, and cloning and sequencing of the complete recA gene.

To facilitate future genetic studies with Streptococcus pyogenes (Sp), a recA mutant (Rec11) was constructed using a streptococcal integration vector carrying a PCR-derived internal recA fragment. The insertion of the plasmid in the mutant chromosome was identified by Southern hybridization. Resistance to UV and the ability to accept linear DNA transformation by Rec11 were greatly decreased, confirming its RecA phenotype. Using the PCR-derived fragment as a probe, we cloned and sequenced the complete Sp recA gene, which is highly homologous to the recA of S. pneumoniae and Lactococcus lactis.