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Atomic charge models for polypeptides derived from ab initio calculations

✍ Scribed by M. N. Bellido; J. A. C. Rullmann

Publisher: John Wiley and Sons
Year: 1989
Tongue: English
Weight: 777 KB
Volume: 10
Category: Article
ISSN: 0192-8651
DOI: 10.1002/jcc.540100405

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✦ Synopsis

Ab Initio charge distributions for amino acid dipeptides are derived utilizing two medium-sized basis sets. Peptide charges differ in two ways from those of existing force fields: the magnitude of the peptide dipole and the dependency on the residue type. The merging of charge distributions of side chain and backbone fragments within a semiclassical model including polarization is investigated. Polarization plays a small, but distinct role in improving the correspondence with ab initio data derived for the complete dipeptide. A description in terms of partly overlapping, interacting fragments correlates well with the ab initio data. The method can be used to derive the electrostatic properties of biological macromolecules by combining accurate descriptions of short range interactions (using good quality basis sets on not too sinall fragments) with good classical models of long range interactions (using multicenter multipole expansions and atomic polarizability tensors). Factors limiting the accuracy of the pyesent representations are discussed.

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