Reference : Nucleotide sequences of the pbpX genes encoding the penicillin-binding proteins 2x fr...
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
Nucleotide sequences of the pbpX genes encoding the penicillin-binding proteins 2x from Streptococcus pneumoniae R6 and a cefotaxime-resistant mutant, C506
Laible, G. [Max-Planck Institut fur Molekulare Genetik > > > >]
Hakenbeck, R. [Max-Planck Institut fur Molekulare Genetik > > > >]
Sicard, M. A. [Université Paul Sabatier - Toulouse 3 - UPS > > > >]
Joris, Bernard mailto [Université de Liège - ULiège > Departement de Microbiologie > > >]
Ghuysen, Jean-Marie [Université de Liège - ULiège > Departement de Microbiologie > > >]
Molecular Microbiology
Blackwell Publishing
Yes (verified by ORBi)
United Kingdom
[en] amino acid sequence ; aminoacyltransferases ; bacterial proteins ; base sequence ; carrier proteins/analysis/*genetics ; cefotaxime/*metabolism ; drug resistance, microbial/genetics ; escherichia coli proteins ; hexosyltransferases ; molecular sequence data ; muramoylpentapeptide carboxypeptidase/analysis/*genetics ; mutation ; penicillin-binding proteins ; penicillins/metabolism ; peptidoglycan glycosyltransferase ; peptidyl transferases ; restriction mapping ; sequence homology, nucleic acid ; serine-type d-ala-d-ala carboxypeptidase ; streptococcus pneumoniae ; transformation, genetic
[en] Development of penicillin resistance in Streptococcus pneumoniae is due to successive mutations in penicillin-binding proteins (PBPs) which reduce their affinity for beta-lactam antibiotics. PBP2x is one of the high-Mr PBPs which appears to be altered both in resistant clinical isolates, and in cefotaxime-resistant laboratory mutants. In this study, we have sequenced a 2564 base-pair chromosomal fragment from the penicillin-sensitive S. pneumoniae strain R6, which contains the PBP2x gene. Within this fragment, a 2250 base-pair open reading frame was found which coded for a protein having an Mr of 82.35kD, a value which is in good agreement with the Mr of 80-85 kD measured by SDS-gel electrophoresis of the PBP2x protein itself. The N-terminal region resembled an unprocessed signal peptide and was followed by a hydrophobic sequence that may be responsible for membrane attachment of PBP2x. The corresponding nucleotide sequence of the PBP2x gene from C504, a cefotaxime-resistant laboratory mutant obtained after five selection steps, contained three nucleotide substitutions, causing three amino acid alterations within the beta-lactam binding domain of the PBP2x protein. Alterations affecting similar regions of Escherichia coli PBP3 and Neisseria gonorrhoeae PBP2 from beta-lactam-resistant strains are known. The penicillin-binding domain of PBP2x shows highest homology with these two PBPs and S. pneumoniae PBP2b. In contrast, the N-terminal extension of PBP2x has the highest homology with E. coli PBP2 and methicillin-resistant Staphylococcus aureus PBP2'. No significant homology was detected with PBP1a or PBP1b of Escherichia coli, or with the low-Mr PBPs.
Fonds de la Recherche Scientifique Médicale - FRSM
Researchers ; Professionals

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