title: Crystal structure of PfbA, a surface adhesin of Streptococcus pneumoniae, provides hints into its interaction with fibronectin.
abstract: PfbA is a surface adhesin and invasin of Streptococcus pneumoniae that binds to human fibronectin and plasminogen of the host extracellular matrix. It is a virulence factor for its pathogenesis. The crystal structure of recombinant PfbA150-607 from S. pneumoniae strain R6, was determined using multiwavelength anomalous dispersion (MAD) method and refined to 1.90Å resolution. The structure of rPfbA150-607 revealed that residues Thr150 to Lys570 form a rigid parallel beta helix, followed by a short disordered region (571-607) that consists of beta hairpins. The structural organization of the beta helix resembles that of polysaccharide-modifying enzymes. The structural and sequence features essential for fibronectin-binding observed in the well characterized fibronectin-binding proteins such as FnBPA of Staphylococcus aureus, SfbI of Streptococcus pyogenes and BBK32 of Borrelia burgdorferi has been found in rPfbA150-607. Based on this, it is predicted that the disordered region following the beta helix could be the fibronectin-binding region in PfbA. PfbA150-607 contains relatively high number of surface exposed lysines and these residues are probably involved in binding plasmin(ogen) as observed in other plasminogen-binding proteins.
authors: Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India.
authors: D S Jemima
authors: DS
authors: Beulin
authors: Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan; Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093-0687, USA.
authors: Masaya
authors: M
authors: Yamaguchi
authors: Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan.
authors: Shigetada
authors: S
authors: Kawabata
authors: Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India. Electronic address: pkarthe@hotmail.com.
authors: Karthe
authors: K
authors: Ponnuraj
mesh_terms: D018829:Adhesins, Bacterial / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D005353:Fibronectins / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D010958:Plasminogen / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013296:Streptococcus pneumoniae / Q000235:genetics / Q000378:metabolism*
chemical_list: D018829:Adhesins, Bacterial; D005353:Fibronectins; D011994:Recombinant Proteins; D010958:Plasminogen
keywords: Crystal structure; Fibronectin-binding; PfbA; S. pneumoniae; Surface adhesin