1nxn
From Proteopedia
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SOLUTION STRUCTURE OF CONTRYPHAN-VN
Overview
The solution structure of contryphan-Vn, a cyclic peptide with a double cysteine S-S bridge and containing a D-tryptophan extracted from the venom of the cone snail Conus ventricosus, has been determined by NMR spectroscopy using a variety of homonuclear and heteronuclear NMR methods and restrained molecular dynamics simulations. The main conformational features of backbone contryphan-Vn are a type IV beta-turn from Gly 1 to Lys 6 and a type I beta-turn from Lys 6 to Cys 9. As already found in other contryphans, one of the two prolines--the Pro4--is mainly in the cis conformation while Pro7 is trans. A small hydrophobic region probably partly shielded from solvent constituted from the close proximity of side chains of Pro7 and Trp8 was observed together with a persistent salt bridge between Asp2 and Lys6, which has been revealed by the diagnostic observation of specific nuclear Overhauser effects. The salt bridge was used as a restraint in the molecular dynamics in vacuum but without inserting explicit electrostatic contribution in the calculations. The backbone of the unique conformational family found of contryphan-Vn superimposes well with those of contryphan-Sm and contryphan-R. This result indicates that the contryphan structural motif represents a robust and conserved molecular scaffold whose main structural determinants are the size of the intercysteine loop and the presence and location in the sequence of the D-Trp and the two Pro residues.
About this Structure
1NXN is a Protein complex structure of sequences from [1] with as ligand. This structure supersedes the now removed PDB entry 1N3V. Full crystallographic information is available from OCA.
Reference
Solution structure of the cyclic peptide contryphan-Vn, a Ca2+-dependent K+ channel modulator., Eliseo T, Cicero DO, Romeo C, Schinina ME, Massilia GR, Polticelli F, Ascenzi P, Paci M, Biopolymers. 2004 Jun 15;74(3):189-98. PMID:15150794
Page seeded by OCA on Thu Feb 21 14:11:17 2008
