## Abstract Using a 6β311G\*\* basis set with estimation of correlation energy at the MP2 level, structural and energetic data for 40 molecular species containing magnesium have been calculated. For about half the species studied, further energetic data were obtained using Pople's G2 method. Enthal
Ab initio molecular orbital studies on the active site of papain
β Scribed by Ria Broer; P.Th. van Duijnen; W.C. Nieuwpoort
- Publisher
- Elsevier Science
- Year
- 1976
- Tongue
- English
- Weight
- 380 KB
- Volume
- 42
- Category
- Article
- ISSN
- 0009-2614
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β¦ Synopsis
Ab initio molecular orbital calcuiations using a contracted basis of gaussian orbitals on the system methanethiol/imidazole are reported. For the hydrogen bond S---H---N in this system, which was chosen as a mode1 for the active site of papain, a double-well potential was found at a S-N separation of 3.35 A. Thii sustains a newly proposed mechanism for the catalytic action of papain which involves the existence of an ion pair II+? 8-_ From minimal basis set calculations on the system methanethiol/imidazole/formaldehyde an estimate is obtained for the stabilization of the first model by the hydrogen bond between imidazole and formaldehyde. In the latter calculations the total energy as a function of proton positions did not show double-well character. The stabilization ener,T tends to reinforce the shape of the potential as obtained in the former calculations. We conclude, however, that minimti basis set calculations are inadequate to elucidate the type of mechanism we are dealing with here.
π SIMILAR VOLUMES
## Abstract The molecular geometry of 1βfluorosilatrane was optimized fully by restricted HartreeβFock (HF) calculations using the 3β21G, 3β21G(__d__) and 6β31G(__d__) basis sets, with the aim of locating the positions of the local minima on the energy hypersurface. The optimized geometries were co
## Abstract __Ab initio__ molecular orbital (__MO__) calculations are carried out on the nonidentity allyl transfer processes, X^β^ + CH~2~CHCH~2~Y β CH~2~CHCH~2~ X + Y^β^, with X^β^ = H, F, and Cl and Y = H, NH~2~, OH, F, PH~2~, SH, and Cl. The Marcus equation applies well to the allyl transfer re
Various dlmer configurations of iluoroform have been mdied by means of the GAUSSIAN-70 &on&n usmg the rnmlmal STO-3G basis set The largest dunenzation energy, 0 68 kul/mol. occurs in an end-to-end bnear geometry wth a H...F distance. of 2 3 A and the electron donor molecule tilted at 45O with respec