GENE ORGANIZATION OF THE STREPTOCOCCUS-PYOGENES PLASMID PDB101 - SEQUENCE-ANALYSIS OF THE ORF-ETA-COPS REGION

The gene organization of the broad-host-range low-copy-number pSM19035 -derived plasmid pDB101 is presented. Analysis of the 19 202-bp sequen ce revealed thirteen different open reading frames (orfs). Nine of the se orfs (repS-orf-orf beta-orf gamma-orf delta-orf epsilon-orf zeta-er m2-erm1 have been previously identified [Ceglowski et al., Gene 136(19 93) 1-12]. The extraordinarily long inverted repeated sequence, which includes orf alpha-orf beta-orf gamma-orf delta-orf epsilon-orf zeta, comprises 76% of the pDB101 molecule. The gene order in pDB101 is repS -orf alpha-orf beta-orf gamma-orf delta-orf epsilon-orf zeta-erm2-erm1 -orf zeta-orf epsilon-orf delta-orf gamma-orf beta-orf alpha-orf eta-o rf theta-orf1-copS. The organization of genes of the orf eta-orf gamma region resembles the organization of genes in the orfA-orfI region of pAM beta 1. Except for Orf1, bands of radioactive proteins correspond ing to the molecular mass of the deduced reading frames (26.7, 14.3 an d 10.3 kDa) were detected using the T7 promoter-expression system. The orf1 encoded a product (deduced molecular mass 28.3 kDa) which shows anomalous electrophoretical mobility corresponding to 60 kDa. The copS - and orf1-encoded proteins share homology to plasmid copy number cont rol systems and Gram(+) cocci surface proteins, respectively. The orf eta and orf theta encode proteins with unknown activity.