Side-chain entropy opposes alpha-helix formation but rationalizes experimentally determined helix-forming propensities.
نویسندگان
چکیده
منابع مشابه
Helix propensities of the amino acids measured in alanine-based peptides without helix-stabilizing side-chain interactions.
Helix propensities of the amino acids have been measured in alanine-based peptides in the absence of helix-stabilizing side-chain interactions. Fifty-eight peptides have been studied. A modified form of the Lifson-Roig theory for the helix-coil transition, which includes helix capping (Doig AJ, Chakrabartty A, Klingler TM, Baldwin RL, 1994, Biochemistry 33:3396-3403), was used to analyze the re...
متن کاملHelix formation in unsolvated peptides: side chain entropy is not the determining factor.
Understanding the factors that stabilize R-helices is critical to understanding protein folding.1 Structure and sequence information for naturally occurring proteins has revealed a preference for certain amino acids in R-helices.2 Thus, many studies have focused on the individual effects of the amino acids on R-helix stability,3,4 and algorithms have been developed that can predict helix conten...
متن کاملHelix propensities of basic amino acids increase with the length of the side-chain.
Helix formation in a 17-residue alanine-lysine peptide and analogous peptides with specific lysine --> X substitutions, where X is 2,3-diamino-L-propionic acid, 2, 4-diamino-L-butyric acid or L-ornithine, have been examined using circular dichroism measurements. The dependence of helix content on X, its position in the sequence, and the number of lysine --> X substitutions are reasonably well d...
متن کاملEnthalpy of helix-coil transition: missing link in rationalizing the thermodynamics of helix-forming propensities of the amino acid residues.
It is known that different amino acid residues have effects on the thermodynamic stability of an alpha-helix. The underlying mechanism for the thermodynamic helical propensity is not well understood. The major accepted hypothesis is the difference in the side-chain configurational entropy loss upon helix formation. However, the changes in the side-chain configurational entropy explain only part...
متن کاملTriple Helix-Forming Oligonucleotide
Triple-helical DNA can be formed by oligonucleotides that bind as third strands of DNA in a sequencespecific manner in the major groove in homopurine/homopyrimidine stretches in duplex DNA. Such triple helix-forming oligonucleotides have been used to inhibit gene expression by blocking transcription factor access to promoter sites in transient expression assays. In an alternative approach to ge...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 1992
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.89.13.5937