ISSN:
0020-7608
Keywords:
ab initio excitation energy
;
five-coordinate vanadate
;
ribonuclease active site
;
effective fragment potential
;
Chemistry
;
Theoretical, Physical and Computational Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Knowledge of the ionicity of the phosphorane intermediate is important to the analysis of the microscopic mechanism of the hydrolysis of the phosphate ester bond by ribonuclease A (RNase A). Five-coordinate uridine vanadate, an analog of the phosphorane, binds to RNase A as the monoanion. The absorption spectra of the vanadate is a probe of the electronic structure of the active site. An in vacuo theoretical model of H4VO5- is calculated to have transitions only in the far ultraviolet (UV). However, H2VO5C2H4- has one in the near UV as well as others further into the UV. The transition energy of the monoanion calculated in the field of the protein active site with effective fragment potentials shifts modestly to the red. Broad monoanion absorptions are predicted which would overlap an observed incomplete very broad absorption attributed to the complex of uridine vanadate with RNase A. The absorption bands of neutral ethylene glycol vanadate are predicted to be further to the red but also overlap the experimental absorption. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 69: 11-19, 1998
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
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