title: Three-dimensional structure of echistatin, the smallest active RGD protein.
abstract: Echistatin is a 49 amino acid protein isolated from the venom of a viper (Echis carinatus) and is one of the smallest natural adhesive ligands that interacts with integrin-type receptors through an Arg-Gly-Asp (RGD) sequence. The structure of echistatin in aqueous solution has been determined by nuclear magnetic resonance spectroscopy. Nuclear Overhauser spectra yielded 490 interatomic distance constraints, which were used in distance geometry calculations. The chain is shown to fold in a series of irregular loops to form a rigid core stabilized by four cystine cross-links. From this core an irregular hairpin and the C-terminus protrude. The core and the hairpin are further stabilized by a network of hydrogen bonds. The RGD sequence is located in a mobile loop at the tip of the hairpin. The mobility and its significance for activity are discussed.
authors.affiliation: Marion Merrell Dow Research Institute, Strasbourg, France.
authors.forename: V
authors.initials: V
authors.lastname: Saudek
authors.forename: R A
authors.initials: RA
authors.lastname: Atkinson
authors.forename: J T
authors.initials: JT
authors.lastname: Pelton
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D003545:Cysteine / Q000378:metabolism; D006860:Hydrogen Bonding; D036341:Intercellular Signaling Peptides and Proteins; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry*; D010455:Peptides; D011487:Protein Conformation; D012911:Snakes; D013057:Spectrum Analysis; D014757:Viper Venoms / Q000737:chemistry*
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D009842:Oligopeptides; D010455:Peptides; D014757:Viper Venoms; C057986:echistatin; C047981:arginyl-glycyl-aspartic acid; D003545:Cysteine