Quantifying the Intrinsic Effects of Two Point Mutation Models of Proline−Proline Diamino Acid Diamide: A First-Principle Computational Study

Two sites of a Pro-Pro diamide were subjected to individual Pro → Thr point mutations. The parent diamide Pro-Pro as well as selected conformers of the Pro-Thr and Thr-Pro mutant models were subjected to molecular computations at the B3LYP/6-31G(d) level of theory. At the optimized geometries, therm...

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Bibliographic Details
Published in:The journal of physical chemistry. B 2007-10, Vol.111 (39), p.11592-11602
Main Authors: Sahai, Michelle A, Viskolcz, Bela, Pai, Emil F, Csizmadia, Imre G
Format: Article
Language:English
Subjects:
Computational Biology
Diamide - analogs & derivatives
Diamide - chemistry
Dipeptides - chemistry
Dipeptides - genetics
Hydrogen Bonding
Models, Chemical
Models, Genetic
Point Mutation
Protein Conformation
Thermodynamics
Threonine - genetics
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Summary:Two sites of a Pro-Pro diamide were subjected to individual Pro → Thr point mutations. The parent diamide Pro-Pro as well as selected conformers of the Pro-Thr and Thr-Pro mutant models were subjected to molecular computations at the B3LYP/6-31G(d) level of theory. At the optimized geometries, thermodynamic functions (S, H, and G) were computed. In order to assess relative stabilities of the mutant models, isodesmic reactions were constructed to calculate ΔS, ΔH, and ΔG, relative to the initial Pro-Pro state. The importance of intramolecular hydrogen bonds, involving the −OH group of the Thr side chain, which emerged after the point mutations were also examined. Our findings suggest a novel approach to analyzing the stability of point mutants in peptide models through the analysis of thermodynamic functions.
ISSN:1520-6106
1520-5207
DOI:10.1021/jp073471h