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 8 July 1988:
Vol. 241. no. 4862, pp. 188 - 191
DOI: 10.1126/science.2455345
Prev | Table of Contents | Next

Articles

Science, Vol 241, Issue 4862, 188-191
Copyright © 1988 by American Association for the Advancement of Science

articles

Three-dimensional structure at 0.86 A of the uncomplexed form of the transmembrane ion channel peptide gramicidin A

DA Langs

Medical Foundation of Buffalo, NY 14203.

The crystal structure of the uncomplexed orthorhombic form of gramicidin A has been determined at 120 K and at 0.86 angstrom resolution. The pentadecapeptide crystallizes as a left-handed antiparallel double-stranded helical dimer with 5.6 amino acid residues per turn. The helix has an overall length of 31 angstroms and an average inner channel diameter of 4.80 angstroms. The channel of this crystalline form is void of ions or solvent molecules. The channel diameter varies from a minimum of 3.85 angstroms to a maximum of 5.47 angstroms and contains three pockets where the cross-channel contacts are 5.25 angstroms or greater. The range of variation seen for the phi and psi torsion angles of the backbone of the helix suggests that these potential ion binding sites can be induced to travel the length of the channel in a peristaltic manner by cooperatively varying these angles. The indole rings of the eight tryptophan residues of the dimer are overlapped in three separate regions on the outer surface of the helix when viewed down the barrel of the channel. This arrangement would permit long-chained lipid molecules to nest parallel to the outer channel surface between these protruding tryptophan regions and act like molecular splines to constrain helical twist deformations of the channel.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
The Preference of Tryptophan for Membrane Interfaces: INSIGHTS FROM N-METHYLATION OF TRYPTOPHANS IN GRAMICIDIN CHANNELS.
H. Sun, D. V. Greathouse, O. S. Andersen, and R. E. Koeppe II (2008)
J. Biol. Chem. 283, 22233-22243
   Abstract »    Full Text »    PDF »
Validation of the single-stranded channel conformation of gramicidin A by solid-state NMR.
F. Kovacs, J. Quine, and T. A. Cross (1999)
PNAS 96, 7910-7915
   Abstract »    Full Text »    PDF »
The conducting form of gramicidin A is a right-handed double-stranded double helix.
B. M. Burkhart, N. Li, D. A. Langs, W. A. Pangborn, and W. L. Duax (1998)
PNAS 95, 12950-12955
   Abstract »    Full Text »    PDF »
High-resolution conformation of gramicidin A in a lipid bilayer by solid-state NMR.
R. Ketchem, W Hu, and T. Cross (1993)
Science 261, 1457-1460
   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 »
Kinetics of gramicidin channel formation in lipid bilayers: transmembrane monomer association.
A. O'Connell, R. Koeppe 2nd, and O. Andersen (1990)
Science 250, 1256-1259
   Abstract »    PDF »
Transmembrane channels based on tartaric acid-gramicidin A hybrids.
C. Stankovic, S. Heinemann, J. Delfino, F. Sigworth, and S. Schreiber (1989)
Science 244, 813-817
   Abstract »    PDF »
Structural polymorphism in transmembrane channels.
F. Salemme (1988)
Science 241, 145
   PDF »


To Advertise     Find Products

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