Journal article
The energetics of ion-pair and hydrogen-bonding interactions in a helical peptide
Biochemistry (Easton), Vol.32(37), pp.9668-9676
09/01/1993
DOI: 10.1021/bi00088a019
PMID: 8373771
Abstract
A single pair of Glu and Lys residues has been placed at four different spacings, and in both orientations, in an otherwise neutral alanine-glutamine peptide helix, and the contribution to helix stability of the different Glu-Lys interactions has been measured. The contribution from the interaction of each charged side chain with the helix macrodipole has also been determined. A side-chain interaction between Gin and Glu, when the spacing is (i, i+4), has been detected and quantified. The interactions have been divided into contributions from hydrogen bonds (independent of the concentration of NaCl) and from electrostatic interactions (present in 10 mM NaCl, absent in 2.5 M NaCl). The major results are as follows: (1) The (i, i+3) and (i, i+4) Glu-Lys interactions are helix-stabilizing and are similar in strength to each other, regardless of the orientation of the side chains. (2) Hydrogen bonds provide the major contribution to these side-chain interactions, as shown by the following facts. First, the major part of the interaction observed in 10 mM NaCl, pH 7, is still present in 2.5 M NaCl. Second, the interaction found at pH 2 is equally as strong as that found in 2.5 M NaCl at pH 7. (3) The (i, i+4) Gln-Glu side-chain hydrogen bond is as strong as the hydrogen-bond component of the Glu-Lys interaction at both pH 2 and pH 7. The Gln-Glu interaction differs from the Glu-Lys interaction in being specific both for the orientation and the spacing of the residues. (4) No significant hydrogen-bonding interaction was found for the (i, i+1) or (i, i+2) Glu-Lys spacings, either at pH 2 or at pH 7, in 2.5 M NaCl. At 10 mM NaCl and pH 7, these spacings show a helix-destabilizing electrostatic interaction which probably results from stabilization of the coil conformation. © 1993, American Chemical Society. All rights reserved.
Details
- Title: Subtitle
- The energetics of ion-pair and hydrogen-bonding interactions in a helical peptide
- Creators
- J. Martin Scholtz - Stanford UniversityHong QianVirginia H RobbinsRobert L Baldwin
- Resource Type
- Journal article
- Publication Details
- Biochemistry (Easton), Vol.32(37), pp.9668-9676
- Publisher
- American Chemical Society
- DOI
- 10.1021/bi00088a019
- PMID
- 8373771
- ISSN
- 0006-2960
- eISSN
- 1520-4995
- Language
- English
- Date published
- 09/01/1993
- Academic Unit
- Research Administration; Pharmaceutical Sciences and Experimental Therapeutics; Biochemistry and Molecular Biology; Chemistry
- Record Identifier
- 9984293090702771
Metrics
7 Record Views