title: comYA, a gene similar to comGA of Bacillus subtilis, is essential for competence-factor-dependent DNA transformation in Streptococcus gordonii.
abstract: Tn4001 mutagenesis identified a new competence gene in Streptococcus gordonii Challis designated comYA. A comYA mutant was completely deficient in transformation and exhibited decreased levels of DNA binding and hydrolysis. The deduced 319-amino-acid ComYA protein exhibited 57% similarity and 33% identity to the ComGA transporter protein of Bacillus subtilis and contained the Walker A-box motif conserved in ATP-binding proteins as well as aspartic acid boxes Asp-1 and Asp-2 present in some components of the general secretory pathway of gram-negative bacteria. comYA appeared to be part of a putative operon encompassing a comGB homolog, designated comYB, together with sequences that could encode ComGC- and ComGD-like peptides designated ComYC and ComYD, respectively, as well as other components. The putative ComYC and ComYD peptides had leader sequences similar to the type IV N-methylphenylalanine pilins of gram-negative bacteria, but unlike other examples in this class, including B. subtilis, they contained an alanine at position -1 of the leader instead of the usual glycine residue. Northern analysis identified a single 6.0-kb comYA-containing transcript strictly dependent on exogenous competence factor for expression in ComA1 cells. An identical pattern of expression was seen in wild-type Challis cells grown under conditions of maximal competence but not in cells that were noncompetent.
authors.affiliation: Oral Infection and Immunity Branch, National Institute of Dental Research, Bethesda, Maryland, USA. Dwayne_Lunsford-1@sbphrd.com
authors.forename: R D
authors.initials: RD
authors.lastname: Lunsford
authors.forename: A G
authors.initials: AG
authors.lastname: Roble
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010641:Phenotype; D012329:RNA, Bacterial / Q000032:analysis / Q000302:isolation & purification; D012689:Sequence Homology, Nucleic Acid; D013298:Streptococcus sanguis / Q000737:chemistry / Q000235:genetics*; D014169:Transformation, Bacterial
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D012329:RNA, Bacterial