title: Sequential 1H NMR assignments and secondary structure of an IgG-binding domain from protein G.
abstract: Protein G is a member of a class of cell surface bacterial proteins from Streptococcus that bind IgG with high affinity. A fragment of molecular mass 6988, which retains IgG-binding activity, has been generated by proteolytic digestion and analyzed by 1H NMR. Two-dimensional DQF-COSY, TOCSY, and NOESY spectra have been employed to assign the 1H NMR spectrum of the peptide. Elements of regular secondary structure have been identified by using nuclear Overhauser enhancement, coupling constant, and amide proton exchange data. The secondary structure consists of a central alpha-helix (Ala28-Val44), flanked by two portions of beta-sheet (Val5-Val26 and Asp45-Lys62). This is a fundamentally different arrangement of secondary structure from that of protein A, which is made up of three consecutive alpha-helices in free solution (Torigoe et al., 1990). We conclude that the molecular mechanisms underlying the association of protein A and protein G with IgG are different.
authors.affiliation: Biological NMR Centre, University of Leicester, U.K.
authors.forename: L Y
authors.initials: LY
authors.lastname: Lian
authors.forename: J C
authors.initials: JC
authors.lastname: Yang
authors.forename: J P
authors.initials: JP
authors.lastname: Derrick
authors.forename: M J
authors.initials: MJ
authors.lastname: Sutcliffe
authors.forename: G C
authors.initials: GC
authors.lastname: Roberts
authors.forename: J P
authors.initials: JP
authors.lastname: Murphy
authors.forename: C R
authors.initials: CR
authors.lastname: Goward
authors.forename: T
authors.initials: T
authors.lastname: Atkinson
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000276:immunology; D007074:Immunoglobulin G / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D011487:Protein Conformation; D013291:Streptococcus / Q000032:analysis
chemical_list: D001426:Bacterial Proteins; C034284:IgG Fc-binding protein, Streptococcus; D007074:Immunoglobulin G