title: Sequencing and characterization of the 185 kDa cell surface antigen of Streptococcus mutans.
abstract: The gene spa P (formerly designated as spa P1) encoding the Mr 185,000 surface antigen I/II of Streptococcus mutans, serotype c (strain NG5) has been sequenced. The deduced amino acid sequence of antigen I/II (1561 residues) includes a putative signal peptide (residues 1-38), as well as a transmembrane region (residues 1537-1556). The N-terminal part of the protein (residues 39-550) is particularly rich in alanine and includes three tandem repeats of a sequence of 82 residues. This region is predicted to be alpha-helical, adopting a coiled-coil formation, and may account for the cell surface hydrophobicity associated with expression of antigen I/II. In contrast the C-terminal region (residues 800-1549) is proline-rich, favouring an extended conformation. Comparison with the sequence determined from Strep. mutans strain MT8148 showed that antigen I/II is highly conserved with the exception of a short central region (residues 750-805). N-terminal sequencing of purified antigens I and II components indicated that antigen I extends from the amino-terminus of the intact Mr 185,000 surface antigen while antigen II extends from residue 996.
authors.affiliation: Department of Immunology, United Medical School, Guy's Hospital, London, England.
authors.forename: C
authors.initials: C
authors.lastname: Kelly
authors.forename: P
authors.initials: P
authors.lastname: Evans
authors.forename: J K
authors.initials: JK
authors.lastname: Ma
authors.forename: L A
authors.initials: LA
authors.lastname: Bergmeier
authors.forename: W
authors.initials: W
authors.lastname: Taylor
authors.forename: L J
authors.initials: LJ
authors.lastname: Brady
authors.forename: S F
authors.initials: SF
authors.lastname: Lee
authors.forename: A S
authors.initials: AS
authors.lastname: Bleiweis
authors.forename: T
authors.initials: T
authors.lastname: Lehner
mesh_terms: D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000235:genetics*; D000954:Antigens, Surface / Q000235:genetics; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics*; D001483:Base Sequence; D005798:Genes, Bacterial / Q000235:genetics*; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D013295:Streptococcus mutans / Q000145:classification / Q000235:genetics / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001426:Bacterial Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C055764:S-layer proteins