title: Structural and functional analysis of the N-terminal domain of the Streptococcus gordonii adhesin Sgo0707.
abstract: The commensal Streptococcus gordonii expresses numerous surface adhesins with which it interacts with other microorganisms, host cells and salivary proteins to initiate dental plaque formation. However, this Gram-positive bacterium can also spread to non-oral sites such as the heart valves and cause infective endocarditis. One of its surface adhesins, Sgo0707, is a large protein composed of a non-repetitive N-terminal region followed by several C-terminal repeat domains and a cell wall sorting motif. Here we present the crystal structure of the Sgo0707 N-terminal domains, refined to 2.1 Å resolution. The model consists of two domains, N1 and N2. The largest domain, N1, comprises a putative binding cleft with a single cysteine located in its centre and exhibits an unexpected structural similarity to the variable domains of the streptococcal Antigen I/II adhesins. The N2-domain has an IgG-like fold commonly found among Gram-positive surface adhesins. Binding studies performed on S. gordonii wild-type and a Sgo0707 deficient mutant show that the Sgo0707 adhesin is involved in binding to type-1 collagen and to oral keratinocytes.
authors.affiliation: Department of Odontology, Division of Oral Microbiology, Umeå University, Umeå, Sweden.
authors.forename: Åsa
authors.initials: Å
authors.lastname: Nylander
authors.forename: Gunnel
authors.initials: G
authors.lastname: Svensäter
authors.forename: Dilani B
authors.initials: DB
authors.lastname: Senadheera
authors.forename: Dennis G
authors.initials: DG
authors.lastname: Cvitkovitch
authors.forename: Julia R
authors.initials: JR
authors.lastname: Davies
authors.forename: Karina
authors.initials: K
authors.lastname: Persson
mesh_terms: D018829:Adhesins, Bacterial / Q000737:chemistry* / Q000378:metabolism; D002473:Cell Wall / Q000737:chemistry; D003001:Cloning, Molecular; D024042:Collagen Type I / Q000378:metabolism; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D054773:Streptococcus gordonii / Q000737:chemistry*
chemical_list: D018829:Adhesins, Bacterial; D024042:Collagen Type I