NUCLEOTIDE AND DEDUCED AMINO-ACID-SEQUENCE OF THE GENE FOR A NOVEL PROTEIN WITH A POSSIBLE REGULATORY FUNCTION ENCODED IN THE BETA-OPERON OF STAPHYLOCOCCUS-AUREUS

Although considerable homology exists between the translation products of the rplL, rpoB and rpoC genes of the beta operons of the Gram-nega tive organism Escherichia coli and the Gram-positive Staphylococcus au reus the region between the rplL and rpoB genes is quite different in the two bacterial species. In E. coli the 324 bp has three centres of dyad symmetry in the first half of the sequence and multiple nonsense codons in all three reading frames. By contrast, the corresponding reg ion in S. aureus consists of 1000 bp capable of forming a similar arra ngement of stem-loop structures but with an open reading frame, sited 177 bp downstream of the end of rplL and 217 bp upstream of the beginn ing of the rpoB gene, with consensus initiation and termination signal s, which if translated would generate a 22,665 Da protein with 202 ami no acids. In view of the inability to find any significant homology wi th other proteins in the data bank and because the evidence suggests, as in E. coli, that the rplL-rpoB intergenic sequence is involved in r egulation it is proposed that the expression product of orf202 may be a further element of control in the S. aureus beta operon.