title: A distinct sortase SrtB anchors and processes a streptococcal adhesin AbpA with a novel structural property.
abstract: Surface display of proteins by sortases in Gram-positive bacteria is crucial for bacterial fitness and virulence. We found a unique gene locus encoding an amylase-binding adhesin AbpA and a sortase B in oral streptococci. AbpA possesses a new distinct C-terminal cell wall sorting signal. We demonstrated that this C-terminal motif is required for anchoring AbpA to cell wall. In vitro and in vivo studies revealed that SrtB has dual functions, anchoring AbpA to the cell wall and processing AbpA into a ladder profile. Solution structure of AbpA determined by NMR reveals a novel structure comprising a small globular α/β domain and an extended coiled-coil heliacal domain. Structural and biochemical studies identified key residues that are crucial for amylase binding. Taken together, our studies document a unique sortase/adhesion substrate system in streptococci adapted to the oral environment rich in salivary amylase.
authors: Departments of Pediatric Dentistry and Microbiology, University of Alabama at Birmingham School of Dentistry, Birmingham, AL, USA.
authors: Xiaobo
authors: X
authors: Liang
authors: Department of Life Sciences, Imperial College London, London, UK.
authors: Bing
authors: B
authors: Liu
authors: Departments of Pediatric Dentistry and Microbiology, University of Alabama at Birmingham School of Dentistry, Birmingham, AL, USA.
authors: Fan
authors: F
authors: Zhu
authors: Department of Oral Biology, University at Buffalo, Buffalo, NY, USA.
authors: Frank A
authors: FA
authors: Scannapieco
authors: Department of Oral Biology, University at Buffalo, Buffalo, NY, USA.
authors: Elaine M
authors: EM
authors: Haase
authors: Department of Life Sciences, Imperial College London, London, UK.
authors: Steve
authors: S
authors: Matthews
authors: Departments of Pediatric Dentistry and Microbiology, University of Alabama at Birmingham School of Dentistry, Birmingham, AL, USA.
authors: Hui
authors: H
authors: Wu
mesh_terms: D020816:Amino Acid Motifs / Q000235:genetics; D019881:Aminoacyltransferases / Q000378:metabolism*; D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D000074041:Microorganisms, Genetically-Modified; D009055:Mouth / Q000382:microbiology*; D009154:Mutation / Q000235:genetics; D059748:Proteolysis; D013291:Streptococcus / Q000502:physiology*; D014774:Virulence
chemical_list: C112818:AbpA protein, Streptococcus gordonii; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C509821:sortase B; D019881:Aminoacyltransferases; D003546:Cysteine Endopeptidases