Identification and Genetic Characterization of a Novel Proteinase, PrtR, from the Human Isolate Lactobacillus rhamnosus BGT10

Irena Pastar, Ivana Tonic, Natasa Golic, Milan Kojic, Richard Van Kranenburg, Michiel Kleerebezem, Ljubisa Topisirovic, Goran Jovanovic

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

A novel proteinase, PrtR, produced by the human vaginal isolate Lactobacillus rhamnosus strain BGT10 was identified and genetically characterized. The prtR gene and flanking regions were cloned and sequenced. The deduced amino acid sequence of PrtR shares characteristics that are common for other cell envelope proteinases (CEPs) characterized to date, but in contrast to the other cell surface subtilisin-like serine proteinases, it has a smaller and somewhat different B domain and lacks the helix domain, and the anchor domain has a rare sorting signal-sequence. Furthermore, PrtR lacks the insert domain, which otherwise is situated inside the catalytic serine protease domain of all CEPs, and has a different cell wall spacer (W) domain similar to that of the cell surface antigen I and II polypeptides expressed by oral and vaginal streptococci. Moreover, the PrtR W domain exhibits significant sequence homology to the consensus sequence that has been shown to be the hallmark of human intestinal mucin protein. According to its α S1 - and β-casein cleavage efficacy, PrtR is an efficient proteinase at pH 6.5 and is distributed throughout all L. rhamnosus strains tested. Proteinase extracts of the BGT10 strain obtained with Ca 2+ -free buffer at pH 6.5 were proteolytically active. The prtR promoter-like sequence was determined, and the minimal promoter region was defined by use of prtR-gusA operon fusions. TheprtR expression is Casitone dependent, emphasizing that nitrogen depletion elevates its transcription. This is in correlation with the catalytic activity of the PrtR proteinase.

Original languageEnglish (US)
Pages (from-to)5802-5811
Number of pages10
JournalApplied and Environmental Microbiology
Volume69
Issue number10
DOIs
StatePublished - Oct 2003

ASJC Scopus subject areas

  • Biotechnology
  • Food Science
  • Applied Microbiology and Biotechnology
  • Ecology

Fingerprint Dive into the research topics of 'Identification and Genetic Characterization of a Novel Proteinase, PrtR, from the Human Isolate Lactobacillus rhamnosus BGT10'. Together they form a unique fingerprint.

Cite this