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Mol Microbiol

Title:		"Competence pheromone, oligopeptide permease, and induction of competence in Streptococcus pneumoniae"
Author(s):		Alloing G; Granadel C; Morrison DA; Claverys JP;
Address:		"Microbiologie et Genetique Moleculaire CNRS-UPR, Universite Paul Sabatler, Toulouse, France"
Journal Title:		Mol Microbiol
Year:		1996
Volume:		21
Issue:		3
Page Number:		471 - 478
DOI:		10.1111/j.1365-2958.1996.tb02556.x
ISSN/ISBN:		0950-382X (Print) 0950-382X (Linking)
Abstract:		"An unmodified heptadecapeptide pheromone capable of eliciting competence for genetic transformation in Streptococcus pneumoniae has recently been identified and characterized. In considering possible signal-transduction mechanisms for the peptide, the previously characterized Ami oligopeptide permease and the three highly homologous oligopeptide-binding lipo-proteins. AmiA, AliA, and AliB, appeared to be good candidates for receptors. We therefore compared the spontaneous transformability of Ami, AliA and AliB mutants to that of an isogenic wild-type strain and we investigated the response of the various mutants to treatment with synthetic competence-stimulating peptide (CSP). Our results clearly demonstrate that neither Ami nor any of the three highly homologous oligopeptide-binding lipoproteins identified so far in S. pneumoniae are required for competence induction following treatment with synthetic CSP. Although the existence of a fourth unidentified oligopeptide-binding lipoprotein and/or a second oligopeptide permease operon could not be completely ruled out, we favour the hypothesis that CSP signal transmission rather involves a two-component regulatory system. Although none of the single or double Ami and All mutants tested appeared severely affected for competence, an exceptional aliB plasmid-insertion mutation abolished competence completely. In addition, the triple AmiA-AliA-AliB mutant differed from wild type in showing no sharp peak of competence but exhibiting transformability throughout the exponential phase of growth. These and previous observations are discussed and a general hypothesis is proposed to account for the modulation of competence by peptide permease mutants in S. pneumoniae"
Keywords:		Bacterial Proteins/*genetics/metabolism Carrier Proteins/*genetics/metabolism DNA-Binding Proteins/*genetics/metabolism Gene Deletion Lipoproteins/*genetics/metabolism Membrane Transport Proteins/*genetics Molecular Sequence Data Oligopeptides/genetics/me;
Notes:		"MedlineAlloing, G Granadel, C Morrison, D A Claverys, J P eng Research Support, U.S. Gov't, Non-P.H.S. England 1996/08/01 Mol Microbiol. 1996 Aug; 21(3):471-8. doi: 10.1111/j.1365-2958.1996.tb02556.x"