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Salt dependence of an α-helical peptide folding energy landscapes

Xiong, K and Asciutto, EK and Madura, JD and Asher, SA (2009) Salt dependence of an α-helical peptide folding energy landscapes. Biochemistry, 48 (45). 10818 - 10826. ISSN 0006-2960

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We used CD,UV resonance Raman spectroscopy, and molecular dynamics simulation to examine the impact of salts on the conformational equilibria and the Ramachandran Ψ angle (un)folding Gibbs free energy landscape coordinate of a mainly polyalanine α-helical peptide, AP of sequence AAAAA-(AAARA)3A. NaClO4 stabilizes α-helical-like conformations more than does NaCl, which stabilizes more than Na 2SO4 at identical ionic strengths. This α-helix stabilization ordering is the reverse of the Hofmeister series of anions in their ability to disorder water hydrogen bonding. Much of the NaClO4 α-helix stabilization results from ClO4- association with the AP terminal-NH3+ groups and Arg side chains. ClO4- stabilizes 310-helix conformations but destabilizes turn conformations. The decreased Cl- and SO 42- AP α-helix stabilization probably results from a decreased association with the Arg and terminal -NH3+ groups. Cl- is expected to have a smaller binding affinity and thus stabilizes α-helical conformations intermediately between NaClO 4 and Na2SO4. Electrostatic screening stabilizes π-bulge conformations. © 2009 American Chemical Society.


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Item Type: Article
Status: Published
CreatorsEmailPitt UsernameORCID
Xiong, K
Asciutto, EK
Madura, JD
Asher, SAasher@pitt.eduASHER
Date: 17 November 2009
Date Type: Publication
Journal or Publication Title: Biochemistry
Volume: 48
Number: 45
Page Range: 10818 - 10826
DOI or Unique Handle: 10.1021/bi9014709
Schools and Programs: Dietrich School of Arts and Sciences > Chemistry
Refereed: Yes
ISSN: 0006-2960
MeSH Headings: Hydrogen Bonding; Peptides--chemistry; Protein Folding; Salts--chemistry; Spectrum Analysis--methods
Other ID: NLM NIHMS207430, NLM PMC2952400
PubMed Central ID: PMC2952400
PubMed ID: 19845367
Date Deposited: 08 Feb 2013 20:49
Last Modified: 22 Jun 2021 13:55


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