Self-protection against cell wall hydrolysis in Streptococcus milleri NMSCC 061 and analysis of the millericin B operon.

ABSTRACT: Streptococcus milleri NMSCC 061 produces an endopeptidase, millericin B, which hydrolyzes the peptide moiety of susceptible cell wall peptidoglycan. The nucleotide sequence of a 4.9-kb chromosomal region showed three open reading frames (ORFs) and a putative tRNA(Leu) sequence. The three ORFs encode a millericin B preprotein (MilB), a putative immunity protein (MilF), and a putative transporter protein (MilT). The milB gene encodes a 277-amino-acid preprotein with an 18-amino-acid signal peptide with a consensus IIGG cleavage motif. The predicted protein encoded by milT is homologous to ABC (ATP-binding cassette) transporters of several bacteriocin systems and to proteins implicated in the signal-sequence-independent export of Escherichia coli hemolysin A. These similarities strongly sugge

SUBMITTER: Beukes M 

PROVIDER: S-EPMC93106 | biostudies-literature | 2001 Sep

REPOSITORIES: biostudies-literature