alpha helix

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alpha helix

A secondary structure of proteins, characterized by a single, spiral chain of amino acids stabilized by hydrogen bonds.

[From alpha-form, the form taken by unstretched protein molecules.]

al′pha-hel′i·cal (-hĕl′ĭ-kəl, -hē′lĭ-) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

alpha helix

(Biochemistry) biochem a helical conformation of a polypeptide chain, found abundantly in the structure of proteins
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

al′pha he′lix

the spatial configuration of many protein molecules in which the polypeptide backbone is stabilized by hydrogen bonds between amino acids in successive helical turns.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
alfa uzvojnica
References in periodicals archive ?
Each subunit consists of two domains; the smaller, thioredoxin-like, N-terminal domain (1-74 residues) is composed of 4 beta-sheets and 4 alpha helices and the C-terminal domain that consists of seven alpha helices.
The number of alpha helices slightly declined, by 2% to 3%, as a result of the processing.
(1995) Intrinsic stability of individual alpha helices modulates structure and stability of the apomyoglobin molten globule form.
In silico analysis of the protein sequence revealed that NcGRA9 exhibits a N-terminal, hydrophobic signal peptide, while the bulk of the protein, with few exceptional sequences, is rather hydrophilic and contains several alpha helices (Figure 3(a)).
Trans-membrane region prediction analysis of TlyA protein by the DAS method showed that the three stretches of seven, 13 and 21 amino-acids (trans-membrane alpha helices) were obtained on the basis of two cut-offs (strict and loose) as plotted in Table 4.
Formation of alpha helices and beta sheets is more difficult when its sequence contains large number of proline.
The usage of sheet-like pentapeptides grows in alpha helices and in random coil due to mutational GC-pressure [14].
Some of those changes lead to the appearance or disappearance of certain hydrogen bonds, frequently making N- and C-termini of beta strands and alpha helices longer or shorter.
Leucine being hydrophobic was found to be buried in protein hydrophobic cores which show a preference for being within alpha helices more so than in beta strands.