title: A new cell surface proteinase: sequencing and analysis of the prtB gene from Lactobacillus delbruekii subsp. bulgaricus.
abstract: Investigation of the chromosomal region downstream of the lacZ gene from Lactobacillus delbrueckii subsp. bulgaricus revealed the presence of a gene (prtB) encoding a proteinase of 1,946 residues with a predicted molecular mass of 212 kDa. The deduced amino acid sequence showed that PrtB proteinase displays significant homology with the N termini and catalytic domains of lactococcal PrtP cell surface proteinases and is probably synthesized as a preproprotein. However, the presence of a cysteine near the histidine of the PrtB active site suggests that PrtB belongs to the subfamily of cysteine subtilisins. The C-terminal region strongly differs from those of PrtP proteinases by having a high lysine content, an imperfect duplication of 41 residues, and a degenerated sequence compared with the consensus sequence for proteins anchoring in the cell walls of gram-positive bacteria. Finally, the product of the truncated prtM-like gene located immediately upstream of the prtB gene seems too short to be involved in the maturation of PrtB.
authors.affiliation: Laboratoire de Microbiologie et Génétique Moléculaire, UMR CNRS 106,Université Claude Bernard-Lyon I, France.
authors.forename: C
authors.initials: C
authors.lastname: Gilbert
authors.forename: D
authors.initials: D
authors.lastname: Atlan
authors.forename: B
authors.initials: B
authors.lastname: Blanc
authors.forename: R
authors.initials: R
authors.lastname: Portailer
authors.forename: J E
authors.initials: JE
authors.lastname: Germond
authors.forename: L
authors.initials: L
authors.lastname: Lapierre
authors.forename: B
authors.initials: B
authors.lastname: Mollet
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D004269:DNA, Bacterial / Q000737:chemistry; D010450:Endopeptidases / Q000737:chemistry / Q000235:genetics*; D005798:Genes, Bacterial; D007778:Lactobacillus / Q000201:enzymology / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D012697:Serine Endopeptidases
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008565:Membrane Proteins; D010450:Endopeptidases; D012697:Serine Endopeptidases; C085783:lactocepin; C099750:PrtB protein, bacteria