THE SSS GENE-PRODUCT, WHICH AFFECTS PYOVERDIN PRODUCTION IN PSEUDOMONAS-AERUGINOSA 7NSK2, IS A SITE-SPECIFIC RECOMBINASE

Pyoverdin production by Pseodomonas aeruginosa strain 7NSK2 was induce d by Zn(ll) in the presence of iron. A mutant was isolated in which Zn (ll) no longer induced pyoverdin production. The sss gene which was in activated in this mutant was cloned and sequenced. Its protein sequenc e showed 50% identity to the XerC protein of Escherichia coil, which i s a member of the lambda integrase family of site-specific recombinase s, An open reading frame was found upstream of sss whose protein seque nce showed strong identity to DapF, the diaminopimelate epimerase. In E. coli, xerC is part of a multicistronic unit that also contains dapF , The sss gene of P. aeruginosa could restore site-specific recombinat ion at cer in an E. coil xerC mutant and the E. coli xerC gene could c omplement a genomic sss mutation in P. aeruginosa.