title: NMR analysis of main-chain conformational preferences in an unfolded fibronectin-binding protein.
abstract: A 130-residue fragment of the Staphylococcus aureus fibronectin-binding protein has been found to exist in a highly unfolded conformation at neutral pH. Measurement of experimental NMR 3JHNalpha coupling constants provides evidence for individual residues having distinct main-chain conformational preferences that are dependent both on the amino acid concerned and on neighbouring residues in the sequence. Analysis shows that these variations in the populations of individual residues can be explained in detail in terms of statistical distributions of conformational states derived from the protein data base. In particular, when the preceding residue has a beta-branched or aromatic side-chain, a significant increase occurs in the population of the less sterically restricted b region of phi,psi space. The results indicate that the local structure of the fibronectin binding protein in solution, under conditions where it displays full activity, approximates very closely to a statistical random coil structure. This may be an important feature in the biological role of this and other polypeptides involved in protein-protein interactions.
authors.affiliation: Oxford Centre for Molecular Sciences and New Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QT, UK.
authors.forename: C J
authors.initials: CJ
authors.lastname: Penkett
authors.forename: C
authors.initials: C
authors.lastname: Redfield
authors.forename: I
authors.initials: I
authors.lastname: Dodd
authors.forename: J
authors.initials: J
authors.lastname: Hubbard
authors.forename: D L
authors.initials: DL
authors.lastname: McBay
authors.forename: D E
authors.initials: DE
authors.lastname: Mossakowska
authors.forename: R A
authors.initials: RA
authors.lastname: Smith
authors.forename: C M
authors.initials: CM
authors.lastname: Dobson
authors.forename: L J
authors.initials: LJ
authors.lastname: Smith
mesh_terms: D018829:Adhesins, Bacterial; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D002352:Carrier Proteins / Q000737:chemistry*; D003198:Computer Simulation; D019992:Databases as Topic; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010446:Peptide Fragments / Q000737:chemistry; D011487:Protein Conformation; D017510:Protein Folding; D013211:Staphylococcus aureus / Q000737:chemistry*
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D002352:Carrier Proteins; D010446:Peptide Fragments; C078635:fibronectin-binding proteins, bacterial