ISSN:
0020-7608
Keywords:
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The paper reports the study of a possible mechanism of Ca+2 activation of prostaglandin PGF2α on the basis of molecular-orbital and conformation-energy calculations. The electronic charges on various atoms of the molecule have been evaluated from the available crystallographic data by the extended Hückel theory (EHT). Conformation energies were calculated for intrinsic torsional rotations around the C11—C12, C7—C8, and C14—C15 bonds. The minimum energy conformation was found to differ from the crystallographic conformation by 9.3 kcal/mol. Some additional local energy minima are also reported within this range. The calculation of the long-range interchain interaction energy between the α and ω chains shows variation with conformation. The binding site for the Ca+2 ion has been estimated on the basis of the molecular electrostatic potentials. Such a binding site was found near the carboxyl group, which agrees with the current chemical thinking. Changes in the electronic charge distribution due to Ca+2 complexation were studied by EHT method using the supramolecular approach. Calcium complexation decreases the conformation energy by 2-3 kcal/mol and has a small effect on the interchain interaction energy.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/qua.560150504
