Structural and Dynamic Characterization of -Conotoxin MVIIA: The Binding Loop Exhibits Slow Conformational Exchange

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• 作者：R. Andrew Atkinson ; Bruno Kieffer ; Annick Dejaegere ; Finton Sirockin ; and Jean-Franç ; ois Lefè ; vre
• 刊名：Biochemistry
• 出版年：2000
• 出版时间：April 11, 2000
• 年：2000
• 卷：39
• 期：14
• 页码：3908 - 3919
• 全文大小：298K
• 年卷期：v.39,no.14(April 11, 2000)
• ISSN：1520-4995

文摘

-Conotoxin MVIIA is a 25-residue, disulfide-bridged polypeptide from the venom of thesea snail Conus magus that binds to neuronal N-type calcium channels. It forms a compact folded structure,presenting a loop between Cys8 and Cys15 that contains a set of residues critical for its binding. The loopdoes not have a unique defined structure, nor is it intrinsically flexible. Broadening of a subset of resonancesin the NMR spectrum at low temperature, anomalous temperature dependence of the chemical shifts ofsome resonances, and exchange contributions to J(0) from ¹³C relaxation measurements reveal thatconformational exchange affects the residues in this loop. The effects of this exchange on the calculatedstructure of -conotoxin MVIIA are discussed. The exchange appears to be associated with a change inthe conformation of the disulfide bridge Cys8-Cys20. The implications for the use of the -conotoxinsas a scaffold for carrying other functions is discussed.