Mutational analysis of class A and class B penicillin-binding proteins in Streptococcus gordonii.

Détails

ID Serval
serval:BIB_83F9008996AA
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Mutational analysis of class A and class B penicillin-binding proteins in Streptococcus gordonii.
Périodique
Antimicrobial Agents and Chemotherapy
Auteur(s)
Haenni M., Majcherczyk P.A., Barblan J.L., Moreillon P.
ISSN
0066-4804[print], 0066-4804[linking]
Statut éditorial
Publié
Date de publication
2006
Volume
50
Numéro
12
Pages
4062-4069
Langue
anglais
Résumé
High-molecular-weight (HMW) penicillin-binding proteins (PBPs) are divided into class A and class B PBPs, which are bifunctional transpeptidases/transglycosylases and monofunctional transpeptidases, respectively. We determined the sequences for the HMW PBP genes of Streptococcus gordonii, a gingivo-dental commensal related to Streptococcus pneumoniae. Five HMW PBPs were identified, including three class A (PBPs 1A, 1B, and 2A) and two class B (PBPs 2B and 2X) PBPs, by homology with those of S. pneumoniae and by radiolabeling with [3H]penicillin. Single and double deletions of each of them were achieved by allelic replacement. All could be deleted, except for PBP 2X, which was essential. Morphological alterations occurred after deletion of PBP 1A (lozenge shape), PBP 2A (separation defect and chaining), and PBP 2B (aberrant septation and premature lysis) but not PBP 1B. The muropeptide cross-link patterns remained similar in all strains, indicating that cross-linkage for one missing PBP could be replaced by others. However, PBP 1A mutants presented shorter glycan chains (by 30%) and a relative decrease (25%) in one monomer stem peptide. Growth rate and viability under aeration, hyperosmolarity, and penicillin exposure were affected primarily in PBP 2B-deleted mutants. In contrast, chain-forming PBP 2A-deleted mutants withstood better aeration, probably because they formed clusters that impaired oxygen diffusion. Double deletion could be generated with any PBP combination and resulted in more-altered mutants. Thus, single deletion of four of the five HMW genes had a detectable effect on the bacterial morphology and/or physiology, and only PBP 1B seemed redundant a priori.
Mots-clé
DNA Mutational Analysis, DNA, Bacterial, Gene Deletion, Genes, Bacterial, Molecular Weight, Penicillin-Binding Proteins/chemistry, Penicillin-Binding Proteins/classification, Streptococcus/chemistry, Streptococcus/classification, Streptococcus/</QualifierName> <QualifierName MajorTopicYN="N">, Transformation, Genetic
Pubmed
Web of science
Open Access
Oui
Création de la notice
24/01/2008 14:54
Dernière modification de la notice
08/05/2019 21:18
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