title: Identification of the Streptococcus gordonii glmM gene encoding phosphoglucosamine mutase and its role in bacterial cell morphology, biofilm formation, and sensitivity to antibiotics.
abstract: Phosphoglucosamine mutase (EC 5.4.2.10) catalyzes the interconversion of glucosamine-6-phosphate into glucosamine-1-phosphate, an essential step in the biosynthetic pathway leading to the formation of peptidoglycan precursor uridine 5'-diphospho-N-acetylglucosamine. The gene (glmM) of Escherichia coli encoding the enzyme has been identified previously. We have now identified a glmM homolog in Streptococcus gordonii, an early colonizer on the human tooth and an important cause of infective endocarditis, and have confirmed that the gene encodes phosphoglucosamine mutase by assaying the enzymatic activity of the recombinant GlmM protein. Insertional glmM mutant of S. gordonii did not produce GlmM, and had a growth rate that was approximately half that of the wild type. Morphological analyses clearly indicated that the glmM mutation causes marked elongation of the streptococcal chains, enlargement of bacterial cells, and increased roughness of the bacterial cell surface. Furthermore, the glmM mutation reduces biofilm formation and increases sensitivity to penicillins relative to wild type. All of these phenotypic changes were also observed in a glmM deletion mutant, and were restored by the complementation with plasmid-borne glmM. These results suggest that, in S. gordonii, mutations in glmM appear to influence bacterial cell growth and morphology, biofilm formation, and sensitivity to penicillins.
authors.affiliation: Department of Pediatric Dentistry, Nippon Dental University School of Life Dentistry at Tokyo, Tokyo, Japan.
authors.forename: Kisaki
authors.initials: K
authors.lastname: Shimazu
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Yoshimori
authors.initials: Y
authors.lastname: Uchikawa
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Shimazu
authors.forename: Ayako
authors.initials: A
authors.lastname: Yajima
authors.forename: Eizo
authors.initials: E
authors.lastname: Takashima
authors.forename: Takaaki
authors.initials: T
authors.lastname: Aoba
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Konishi
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D017353:Gene Deletion; D005816:Genetic Complementation Test; D005944:Glucosamine / Q000031:analogs & derivatives / Q000378:metabolism; D019298:Glucose-6-Phosphate / Q000031:analogs & derivatives / Q000378:metabolism; D008853:Microscopy; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010406:Penicillins / Q000494:pharmacology; D010733:Phosphoglucomutase / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D054773:Streptococcus gordonii / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D014537:Uridine Diphosphate N-Acetylglucosamine / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D010406:Penicillins; D011994:Recombinant Proteins; C001293:glucosamine 6-phosphate; D014537:Uridine Diphosphate N-Acetylglucosamine; D019298:Glucose-6-Phosphate; C097631:phosphoglucosamine mutase; D010733:Phosphoglucomutase; D005944:Glucosamine