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Energetics of hydrogen bonding in proteins: A model compound study
Author(s) -
Habermann Susan M.,
Murphy Kenneth P.
Publication year - 1996
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560050702
Subject(s) - amide , chemistry , hydrogen bond , energetics , low barrier hydrogen bond , peptide bond , crystallography , stereochemistry , molecule , organic chemistry , thermodynamics , physics , enzyme
Differences in the energetics of amide‐amide and amide‐hydroxyl hydrogen bonds in proteins have been explored from the effect of hydroxyl groups on the structure and dissolution energetics of a series of crystalline cyclic dipeptides. The calorimetrically determined energetics are interpreted in light of the crystal structures of the studied compounds. Our results indicate that the amide‐amide and amide‐hydroxyl hydrogen bonds both provide considerable enthalpic stability, but that the amide‐amide hydrogen bond is about twice that of the amide‐hydroxyl. Additionally, the interaction of the hydroxyl group with water is seen most readily in its contributions to entropy and heat capacity changes. Surprisingly, the hydroxyl group shows weakly hydrophobic behavior in terms of these contributions. These results can be used to understand the effects of mutations on the stability of globular proteins.