Home > Archives > Additional Archives > Mireia Garcia-Viloca   Mireia Garcia-Viloca Dept of Chemistry University of Minnesota Garcia@chem.umn.edu Abstract: Quantum Dynamics Study of Hydride Transfer Reaction in Xylose Isomerase We have used a combined QM/MM and variational transition state theory to study the quantum mechanical tunneling effects on the hydride transfer reaction in xylose isomerase. Although the importance of quantum mechanical tunneling and zero point energy effects in kinetics is widely appreciated, these contributions have been mostly excluded in simulations of protein dynamics. The methodology used in this study provides a practical way to include quantum effects in molecular dynamics simulations of enzyme rate constants. D-xylose isomerase is an extensively utilized enzyme in industry in the production of high-fructose corn syrup, due to its ability to isomerize D-glucose into D-fructose. Its mechanistic interest originates from the fact that it appears to catalyze an isomerization reaction by a hydride shift promoted by a bridged metallic center. One of the two essential magnesium ions per active site has been observed to occupy two alternate positions, separated by 1.8 Å. It is not known when and how this movement takes place along the isomerization. Our results indicate the existence of a breathing motion of the cations during the hydride transfer reaction. We have used this computational method to predict the kinetic isotopic effects (KIEs), agreement with experimental data further validates our method. This is a joint work with Dr. Cristóbal Alhambra, Prof. Donald Truhlar and Prof. Jiali Gao at the University of Minnesota, during a Fulbright Study.
	Home | SDSC | UCSD | Campus Map | Contact Info
	The San Diego Supercomputer Center (SDSC) is a research unit of the University of California, San Diego, and the leading-edge site of the National Partnership for Advanced Computational Infrastructure. SDSC researchers conduct studies in computational science, develop high-performance computing and networking technologies, and participate in NPACI activities. SDSC -- UC San Diego, MC 0505 -- 9500 Gilman Drive -- La Jolla, CA 92093-0505 -- 858-534-5000 -- 858-534-5152 (fax) info@sdsc.edu © 2001, The Regents of the University of California