Deletion in sortase gene of Streptococcus mutans Ingbritt.
Our previous studies on Streptococcus mutans have demonstrated that surface proteins containing a C-terminal sorting signal, such as surface protein antigen (PAc), glucan-binding protein C (GbpC) and dextranase (Dex), are anchored to the cell wall by a sortase (SrtA). In this study we found that, unlike other strains of S. mutans, strain Ingbritt did not exhibit cell wall-anchoring of PAc, GbpC and Dex. It is speculated that the SrtA of strain Ingbritt did not function in the cell wall-anchoring process of these surface proteins. Sequence analysis revealed a deletion of an 11-bp nucleotide sequence in the srtA gene of strain Ingbritt, resulting in the generation of a new termination codon, resulting in production of an incomplete SrtA enzyme protein. As a result, strain Ingbritt showed a localization change of PAc, GbpC and Dex in the cell, implying that strain Ingbritt loses the biological functions mediated by the cell surface-associated proteins of S. mutans. These results suggest that strain Ingbritt could be less cariogenic than other strains of S. mutans.
Igarashi
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Department of Oral Microbiology, Showa University School of Dentistry, Tokyo, Japan. igatakes@dent.showa-u.ac.jp
D019881:Aminoacyltransferases / Q000235:genetics*; D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D020029:Base Pairing / Q000235:genetics; D001483:Base Sequence / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics; D002473:Cell Wall / Q000378:metabolism; D003062:Codon / Q000235:genetics; D003546:Cysteine Endopeptidases; D003910:Dextranase / Q000235:genetics; D000939:Epitopes / Q000235:genetics; D017353:Gene Deletion; D005798:Genes, Bacterial / Q000235:genetics*; D006801:Humans; D037102:Lectins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000235:genetics; D013295:Streptococcus mutans / Q000145:classification / Q000201:enzymology* / Q000235:genetics
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D002352:Carrier Proteins; D003062:Codon; D000939:Epitopes; D037102:Lectins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C055764:S-layer proteins; C037937:glucan-binding proteins; D019881:Aminoacyltransferases; C120542:sortase A; D003910:Dextranase; D003546:Cysteine Endopeptidases