title: Cloning of the Streptococcus mutans gene encoding glucan binding protein B and analysis of genetic diversity and protein production in clinical isolates.
abstract: Streptococcus mutans, the primary etiological agent of dental caries, produces several activities that promote its accumulation within the dental biofilm. These include glucosyltransferases, their glucan products, and proteins that bind glucan. At least three glucan binding proteins have been identified, and GbpB, the protein characterized in this study, appears to be novel. The gbpB gene was cloned and the predicted protein sequence contained several unusual features and shared extensive homology with a putative peptidoglycan hydrolase from group B streptococcus. Examination of gbpB genes from clinical isolates of S. mutans revealed that DNA polymorphisms, and hence amino acid changes, were limited to the central region of the gene, suggesting functional conservation within the amino and carboxy termini of the protein. The GbpB produced by clinical isolates and laboratory strains showed various distributions between cells and culture medium, and amounts of protein produced by individual strains correlated positively with their ability to grow as biofilms in an in vitro assay.
authors.affiliation: Department of Immunology, The Forsyth Institute, Boston, Massachusetts 02115, USA.
authors.forename: R O
authors.initials: RO
authors.lastname: Mattos-Graner
authors.forename: S
authors.initials: S
authors.lastname: Jin
authors.forename: W F
authors.initials: WF
authors.lastname: King
authors.forename: T
authors.initials: T
authors.lastname: Chen
authors.forename: D J
authors.initials: DJ
authors.lastname: Smith
authors.forename: M J
authors.initials: MJ
authors.lastname: Duncan
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D018441:Biofilms / Q000254:growth & development*; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics*; D002648:Child; D003001:Cloning, Molecular; D004269:DNA, Bacterial; D005798:Genes, Bacterial; D014644:Genetic Variation; D016680:Genome, Bacterial; D006801:Humans; D037102:Lectins; D008969:Molecular Sequence Data; D012150:Polymorphism, Restriction Fragment Length; D017386:Sequence Homology, Amino Acid; D013290:Streptococcal Infections / Q000382:microbiology*; D013295:Streptococcus mutans / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D037102:Lectins; C037937:glucan-binding proteins