ESTRIN Dario Ariel
congresos y reuniones científicas
conferencia invitada: Chemical reactivity of heme proteins
M.A. MARTI; A. CRESPO; L. CAPECE; D.E. BIKIEL; D.A. ESTRIN
Conferencia; 13th International Workshop on Computational Physics and Materials Science: Total Energy and Force Methods; 2007
International Center for Theoretical Physics
Exploring Chemical Reactivity in Biological Systems with hybrid QM/MMMethodsM.A. Marti, A. Crespo, L. Capece, D.A. Bikiel, D.A. EstrinDepartamento de Química Inorgánica, Analítica y Química Física, INQUIMAECONICET,Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires,Ciudad Universitaria, pab. 2, C1428EHA, ArgentinaWe present a hybrid Quantum Mechanics Molecular Mechanics (QM/MM)implementation developed to deal with large molecular complexes. It is particularlysuited to study relatively large systems in which the environment effects are important,as in the case of an enzyme active site immersed in a protein matrix, or a solute in acondensed phase. In the QM/MM scheme, a region of the system receives a quantummechanicaldescription, while the environment is treated at the molecular mechanicslevel using the biomolecules Amber force field. The QM calculations are performedwith the SIESTA code, a DFT scheme based on finite basis sets and pseudopotentials,which makes the overall implementation very efficient. We will present results obtainedwith this scheme for the following problems:(i) conversion of chorismate to prephenate catalyzed by the enzyme chorismate mutaseof Bacillus Subtilus. (ii) modulation of oxygen affinity in heme proteins by proximal,distal and dynamical effects. (iii) detoxification of nitric oxide by the truncatedhemoglobin N of Mycobacterium Tuberculosis.