title: Two distinct structures of alpha-conotoxin GI in aqueous solution.
abstract: The detailed analysis of conformational space of alpha-conotoxin GI in aqueous solution has been performed on the basis of two-dimensional NMR spectroscopy data using multiconformational approach. As the result, two topologically distinct interconvertible sets of GI conformations (populations of 78% and 22%) have been found. A common feature of the two sets is the Asn4-Cys7 beta-turn. The Gly8 to Tyrll region has a structure of right-handed helical turn in the major set and two sequential bends in the minor one. N-terminus and C-terminus also have different orientations, anti-parallel in the major conformational set and parallel in the minor one. An average pairwise rmsd for backbone heavy atoms is 0.56 A in the major set, 0.23 A in the minor, and 1.85 A between the structures of the two sets. The X-ray structure of GI [Guddat, L. W., Martin, J. A., Shan, L., Edmundson, A. B. & Gray, W. R. (1996) Biochemistry 35, 11329 - 11335] has the same folding pattern as the major NMR set, the average backbone rmsd between the two structures being 0.77 A.
authors.affiliation: Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow.
authors.forename: I V
authors.initials: IV
authors.lastname: Maslennikov
authors.forename: A G
authors.initials: AG
authors.lastname: Sobol
authors.forename: K V
authors.initials: KV
authors.lastname: Gladky
authors.forename: A A
authors.initials: AA
authors.lastname: Lugovskoy
authors.forename: A G
authors.initials: AG
authors.lastname: Ostrovsky
authors.forename: V I
authors.initials: VI
authors.lastname: Tsetlin
authors.forename: V T
authors.initials: VT
authors.lastname: Ivanov
authors.forename: A S
authors.initials: AS
authors.lastname: Arseniev
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020916:Conotoxins; D018360:Crystallography, X-Ray; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008978:Mollusk Venoms / Q000138:chemical synthesis / Q000737:chemistry*; D010456:Peptides, Cyclic / Q000138:chemical synthesis / Q000737:chemistry*; D011487:Protein Conformation; D012996:Solutions; D014867:Water
chemical_list: D020916:Conotoxins; D008978:Mollusk Venoms; D010456:Peptides, Cyclic; D012996:Solutions; D014867:Water; C029960:conotoxin GI