Publication Date:
1990-08-13
Description:
The three-dimensional structure of charybdotoxin, a high-affinity peptide blocker of several potassium ion channels, was determined by two-dimensional nuclear magnetic resonance (2-D NMR) spectroscopy. Unambiguous NMR assignments of backbone and side chain hydrogens were made for all 37 amino acids. The structure was determined by distance geometry and refined by nuclear Overhauser and exchange spectroscopy back calculation. The peptide is built on a foundation of three antiparallel beta strands to which other parts of the sequence are attached by three disulfide bridges. The overall shape is roughly ellipsoidal, with axes of approximately 2.5 and 1.5 nanometers. Nine of the ten charged groups are located on one side of the ellipsoid, with seven of the eight positive residues lying in a stripe 2.5 nanometers in length. The other side displays three hydrophobic residues projecting prominently into aqueous solution. The structure rationalizes several mechanistic features of charybdotoxin block of the high-conductance Ca2(+)-activated K+ channel.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Massefski, W Jr -- Redfield, A G -- Hare, D R -- Miller, C -- GM-20168/GM/NIGMS NIH HHS/ -- GM-31768/GM/NIGMS NIH HHS/ -- RR0031/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 3;249(4968):521-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Graduate Department of Biochemistry, Brandeis University, Waltham, MA 02254.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1696395" target="_blank"〉PubMed〈/a〉
Keywords:
Amino Acid Sequence
;
Charybdotoxin
;
Disulfides/analysis
;
Magnetic Resonance Spectroscopy/methods
;
Models, Molecular
;
Molecular Sequence Data
;
Potassium Channels/drug effects
;
Protein Conformation
;
*Scorpion Venoms/pharmacology
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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