Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Site Tools

  • AAAS
  • Subscribe
  • Feedback

Site Search

Search Advanced

Science 3 August 1990:
Vol. 249. no. 4968, pp. 521 - 524
DOI: 10.1126/science.1696395
Prev | Table of Contents | Next

Articles

Science, Vol 249, Issue 4968, 521-524
Copyright © 1990 by American Association for the Advancement of Science

articles

Molecular structure of charybdotoxin, a pore-directed inhibitor of potassium ion channels

W Massefski Jr, AG Redfield, DR Hare, and C Miller

Graduate Department of Biochemistry, Brandeis University, Waltham, MA 02254.

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.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Refined structure of charybdotoxin: common motifs in scorpion toxins and insect defensins.
F Bontems, C Roumestand, B Gilquin, A Menez, and F Toma (1991)
Science 254, 1521-1523
   Abstract »    PDF »
Crystal structure of defensin HNP-3, an amphiphilic dimer: mechanisms of membrane permeabilization.
C. Hill, J Yee, M. Selsted, and D Eisenberg (1991)
Science 251, 1481-1485
   Abstract »    PDF »
Mutations affecting TEA blockade and ion permeation in voltage-activated K+ channels.
R MacKinnon and G Yellen (1990)
Science 250, 276-279
   Abstract »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)