Sequence analysis and characterization of a novel fibronectin-binding repeat domain from the surface of Streptococcus pneumoniae

• Published in: Omics (Larchmont, N.Y.) Vol. 8; no. 4; p. 341
• Main Authors: Bumbaca, Daniela, Littlejohn, James E, Nayakanti, Hannah, Rigden, Daniel J, Galperin, Michael Y, Jedrzejas, Mark J
• Format: Journal Article
• Language: English
• Published: United States 01.12.2004
• Subjects: Adhesins, Bacterial - chemistry; Amino Acid Sequence; Animals; Bacterial Adhesion; Bacterial Outer Membrane Proteins - chemistry; Bacterial Proteins - chemistry; Cell Membrane - metabolism; Cloning, Molecular; Collagen - chemistry; Computational Biology - methods; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Escherichia coli - metabolism; Fibronectins - chemistry; Fibronectins - metabolism; Flow Cytometry; Humans; Mice; Models, Molecular; Molecular Sequence Data; Phylogeny; Protein Binding; Protein Structure, Secondary; Protein Structure, Tertiary; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Sequence Homology, Nucleic Acid; Species Specificity; Streptococcus pneumoniae - metabolism; Streptococcus pneumoniae - pathogenicity
• ISSN: 1536-2310; 1557-8100
• DOI: 10.1089/omi.2004.8.341

Streptococcus pneumoniae open reading frame SP0082 encodes a surface protein that contains four copies of a novel conserved repeat domain that bears no significant sequence similarity to proteins of known function. Homologous sequences from other streptococci contain two to six of these repeats, designated the SSURE (streptococcal surface repeat) domain. To investigate the functional role(s) of this domain, the third SSURE repeat of SP0082 sequence has been expressed in Escherichia coli, purified to homogeneity and characterized by biochemical and immunological methods. The expressed protein fragment was found to bind to fibronectin, but not to collagen or submaxillary mucin. Anti-SSURE antibodies recognized the corresponding protein on the surface of pneumococcal cells. These data identify S. pneumoniae SP0082 protein and its homologs in other streptococci as fibronectin-binding surface adhesins. The SSURE domain is likely to contain a novel protein fold, which was tentatively modeled using ab initio modeling methods.