Two distinct structures of alpha-conotoxin GI in aqueous solution.
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.
Maslennikov
I V
IV
Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow.
Sobol
A G
AG
Gladky
K V
KV
Lugovskoy
A A
AA
Ostrovsky
A G
AG
Tsetlin
V I
VI
Ivanov
V T
VT
Arseniev
A S
AS
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
D020916:Conotoxins; D008978:Mollusk Venoms; D010456:Peptides, Cyclic; D012996:Solutions; D014867:Water; C029960:conotoxin GI