COMPETENCE FOR GENETIC-TRANSFORMATION IN ENCAPSULATED STRAINS OF STREPTOCOCCUS-PNEUMONIAE - 2 ALLELIC VARIANTS OF THE PEPTIDE PHEROMONE

The nucleotide sequence of comC, the gene encoding the 17-residue comp etence-stimulating peptide (CSP) of Streptococcus pneumoniae (L. S. Ha varstein, G. Coomaraswamy, and D. A. Morrison, Proc. Natl. Acad. Sci. USA 92:11140-11144, 1995) was determined with 42 encapsulated strains of different serotypes. A new allele, comC2, was found in 13 strains, including the type 3 Avery strain, A66, while all others carried a gen e (now termed comC1) identical to that originally described for strain Rx1. The predicted mature product of comC2 is also a heptadecapeptide but differs from that of comC1 at eight residues. Both CSP-1 and CSP- 2 synthetic peptides were used to induce competence in the 42 strains; 48% of the strains became competent after the addition of the synthet ic peptide, whereas none were transformable without the added peptides .