Development and application of computer simulation and spectroscopical analysis to study metalloenzymes and flexible proteins

Abstract

There is an increasing importance of computer simulation in the areas of chemistry, biochemistry and molecular biophysics. The Nobel Prize in Chemistry awarded in 2013 for the development of hybrid methods of molecular simulation is a clear recognition of this importance.The research proposal presented here will be carried out in the Computational Biochemistry and Biophysics laboratory recently installed in the Instituto de Química da Universidade de São Paulo (IQ-USP) and contains five fellow students that already work in the laboratory (1 post-doc, 3 graduate and 1 undergraduate), besides international collaborators. The project focus on the development and the application of innovative molecular simulation methods.We propose to study important biomolecules involved in energetic and molecular recognition processes. The two main metalloproteins studied are rubredoxin and cytochrome bc1 (or mitochondrial complex III). We will investigate electronic phenomena associated with theirs prosthetic groups, iron-sulfur clusters, by molecular simulation with descriptions of hybrid potential of quantum chemistry and molecular mechanics (QC/MM), as well as by approximations proposed and implemented by us to allow the study of metalloproteins. We will also study the structural flexibility and complexation to small ligands of the human phosphatase Cdc25B that is a possible target for the development of antineoplastic inhibitors.For rubredoxin, we will continue the investigation of its forced unfolding in comparison to atomic force microscopy (AFM) experiments. The anisotropic dependence of unfolding and the action of chemical agents in the stability of Fe-S bonds in rubredoxin will be studied. For cytochrome bc1, we plan to elucidate the molecular mechanism of the Q cycle, and the associated coupled electron and proton transfers involving its ubiquinone substrate. The pathway for diffusion and the stoichiometry of complexation between ubiquinone and its redox centers in cytochrome bc1 will also be investigated. For Cdc25B, we will develop procedures to incorporate experimental data derived from nuclear magnetic resonance (NMR) in computer modelling of its structure and complexation to inhibitors. (AU)