Publication
Title
Local softness, softness dipole, and polarizabilities of functional groups: application to the side chains of the 20 amino acids
Author
Abstract
The values of molecular polarizabilities and softnesses of the 20 amino acids were computed ab initio (MP2). By using the iterative Hirshfeld scheme to partition the molecular electronic properties, we demonstrate that the values of the softness of the side chain of the 20 amino acids are clustered in groups reflecting their biochemical classification, namely: aliphatic, basic, acidic, sulfur containing, and aromatic amino acids. The present findings are in agreement with previous results using different approximations and partitioning schemes [P. Senet and F. Aparicio, J. Chem. Phys. 126, 145105 (2007)]. In addition, we show that the polarizability of the side chain of an amino acid depends mainly on its number of electrons (reflecting its size) and consequently cannot be used to cluster the amino acids in different biochemical groups, in contrast to the local softness. Our results also demonstrate that the global softness is not simply proportional to the global polarizability in disagreement with the intuition that a softer moiety is also more polarizable. Amino acids with the same softness may have a polarizability differing by a factor as large as 1.7. This discrepancy can be understood from first principles as we show that the molecular polarizability depends on a softness dipole vector and not simply on the global softness.
Language
English
Source (journal)
The journal of chemical physics. - New York, N.Y.
Publication
New York, N.Y. : 2009
ISSN
0021-9606
Volume/pages
131:4(2009), p. 044312,1-044312,11
ISI
000268613700043
Full text (Publisher's DOI)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
E-info
Web of Science
Record
Identification
Creation 09.09.2009
Last edited 13.07.2017
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