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.

Science 16 June 1989:
Vol. 244. no. 4910, pp. 1333 - 1337
DOI: 10.1126/science.2734612
Prev | Table of Contents | Next

Articles

Science, Vol 244, Issue 4910, 1333-1337
Copyright © 1989 by American Association for the Advancement of Science

articles

Water-inserted alpha-helical segments implicate reverse turns as folding intermediates

M Sundaralingam and YC Sekharudu

Department of Biochemistry, University of Wisconsin-Madison 53706.

Information relevant to the folding and unfolding of alpha helices has been extracted from an analysis of protein structures. The alpha helices in protein crystal structures have been found to be hydrated, either externally by a water molecule hydrogen bonding to the backbone carbonyl oxygen atom, or internally by inserting into the helix hydrogen bond and forming a hydrogen-bonded bridge between the backbone carbonyl oxygen and the amide nitrogen atoms. The water-inserted alpha-helical segments display a variety of reverse-turn conformations, such as type III, type II, type I, and opened out, that can be considered as folding intermediates that are trapped in the folding-unfolding process of alpha helices. Since the alpha helix, most turns, and the extended beta strand occupy contiguous regions in the conformational space of phi, psi dihedral angles, a plausible pathway can be proposed for the folding-unfolding process of alpha helices in aqueous solution.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
3dSS: 3D structural superposition..
K. Sumathi, P. Ananthalakshmi, M. N. A. Md. Roshan, and K. Sekar (2006)
Nucleic Acids Res. 34, W128-W132
   Abstract »    Full Text »    PDF »
Novel protein structural motifs containing two-turn and longer 310-helices.
L. Pal and G. Basu (1999)
Protein Eng. Des. Sel. 12, 811-814
   Abstract »    Full Text »    PDF »
Water: Foldase activity in catalyzing polypeptide conformational rearrangements.
F. Xu and T. A. Cross (1999)
PNAS 96, 9057-9061
   Abstract »    Full Text »    PDF »
Structural characterization by computer experiments of the lipid-free LDL-receptor-binding domain of apolipoprotein E.
M. Prevost and J.-P. Kocher (1999)
Protein Eng. Des. Sel. 12, 475-483
   Abstract »    Full Text »    PDF »
alpha -Helical stabilization by side chain shielding of backbone hydrogen bonds.
A. E. Garcia and K. Y. Sanbonmatsu (2002)
PNAS 99, 2782-2787
   Abstract »    Full Text »    PDF »


To Advertise     Find Products

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