title: 1H 2D NMR and distance geometry study of the folding of Ecballium elaterium trypsin inhibitor, a member of the squash inhibitors family.
abstract: The solution conformation of synthetic Ecballium elaterium trypsin inhibitor II, a 28-residue peptide with 3 disulfide bridges, has been studied by 1H 2D NMR measurements. Secondary structure elements were determined: a miniantiparallel beta-sheet Met 7-Cys 9 and Gly 25-Cys 27, a beta-hairpin 20-28 with beta-turn 22-25, and two tight turns Asp 12-Cys 15 and Leu 16-Cys 19. A set of interproton distance restraints deduced from two-dimensional nuclear Overhauser enhancement spectra and 13 phi backbone torsion angles restraints were used as the basis of three-dimensional structure computations including disulfide bridges arrangement by using distance geometry calculations. Computations for the 15 possible S-S linkage combinations lead to the proposal of the array 2-19, 9-21, 15-27 as the most probable structure for EETI II.
authors.affiliation: Centre CNRS-INSERM de Pharmacologie-Endocrinologie, Montpellier, France.
authors.forename: A
authors.initials: A
authors.lastname: Heitz
authors.forename: L
authors.initials: L
authors.lastname: Chiche
authors.forename: D
authors.initials: D
authors.lastname: Le-Nguyen
authors.forename: B
authors.initials: B
authors.lastname: Castro
mesh_terms: D000595:Amino Acid Sequence; D006859:Hydrogen; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010940:Plant Proteins; D010944:Plants; D011487:Protein Conformation; D014361:Trypsin Inhibitors
chemical_list: D010940:Plant Proteins; D014361:Trypsin Inhibitors; C031809:trypsin inhibitor, Cucurbita sp.; D006859:Hydrogen