Journal article
Kinetics of amide proton exchange in helical peptides of varying chain lengths. Interpretation by the Lifson-Roig equation
Biochemistry (Easton), Vol.31(5), pp.1263-1269
02/01/1992
DOI: 10.1021/bi00120a001
PMID: 1310608
Abstract
The kinetics of amide proton exchange (1H→2H) have been measured by proton nuclear magnetic resonance spectroscopy for a set of helical peptides with the generic formula Ac-(AAKAA)mY-NH2 and with chain lengths varying from 6 to 51 residues. The integrated intensity of the amide resonances has been measured as a function of time in 2H2O at pH* 2.50. Exchange kinetics for these peptides can be modeled by applying the Lifson-Roig treatment for the helix-to-coil transition. The Lifson-Roig equation is used to compute the probability that each residue is helical, as defined by its backbone (Φ, Ψ) angles. A recursion formula then is used to find the probability that the backbone amide proton of each residue is hydrogen bonded. The peptide helix can be treated as a homopolymer, and direct exchange from the helix can be neglected. The expression for the exchange kinetics contains only three unknown parameters: the rate constant for exchange of a non-hydrogen-bonded (random coil) backbone amide proton and the nucleation (v2) and propagation (w) parameters of the Lifson-Roig theory. The fit of the exchange curves to these three parameters is very good, and the values for v2 and w agree with those derived from circular dichroism studies of the thermally-induced unfolding of related peptides. © 1992, American Chemical Society. All rights reserved.
Details
- Title: Subtitle
- Kinetics of amide proton exchange in helical peptides of varying chain lengths. Interpretation by the Lifson-Roig equation
- Creators
- Carol A Rohl - Stanford UniversityJ. Martin ScholtzEunice J YorkJohn M StewartRobert L Baldwin
- Resource Type
- Journal article
- Publication Details
- Biochemistry (Easton), Vol.31(5), pp.1263-1269
- Publisher
- American Chemical Society
- DOI
- 10.1021/bi00120a001
- PMID
- 1310608
- ISSN
- 0006-2960
- eISSN
- 1520-4995
- Language
- English
- Date published
- 02/01/1992
- Academic Unit
- Research Administration; Pharmaceutical Sciences and Experimental Therapeutics; Biochemistry and Molecular Biology; Chemistry
- Record Identifier
- 9984288734502771
Metrics
5 Record Views