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Proton affinity of amino acids: Their interpretation with density functional theory‐based descriptors
Author(s) -
Baeten A.,
De Proft F.,
Geerlings P.
Publication year - 1996
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1996)60:4<931::aid-qua14>3.0.co;2-7
Subject(s) - electronegativity , proton affinity , chemistry , density functional theory , proton , amino acid , functional group , group (periodic table) , computational chemistry , stereochemistry , crystallography , organic chemistry , protonation , ion , biochemistry , physics , quantum mechanics , polymer
The calculation of group electronegativity and hardness for amino acid “functional groups,” considered as a biradical taken out of their protein environment, is performed for both the α‐helix and β‐sheet geometry of these amino acids. Group electronegativity and hardness are then used to interpret the experimental gas‐phase proton affinity sequence of the amino acids. Group hardness was found to play the dominant role, whereas group electronegativity only had a minor influence on the sequence, thereby stressing the importance of the charged form in the acid‐base equilibrium. An explanation for the deviations, seen for some of the amino acids, from the correlation between these group properties and the proton affinity was sought. © 1996 John Wiley & Sons, Inc.