Structural and Dynamical Study of Extreme Conditions Adapted Hemeproteins Using Computer Simulation Techniques

BUSTAMANTE, JUAN PABLO; BOECHI, LEONARDO; MARTÍ, MARCELO ADRIÁN; ESTRIN, DARÍO

Workshop; 4º Workshop de Química Bioinorgánica: Aspectos estructurales y funcionales de sistemas bioinorgánicos estudiados mediante métodos espectroscópicos, de cálculo, y sistemas modelo; 2010

In nature there are organisms that are adapted to live at extreme temperature conditions. These organisms however, share proteins which are evolutionary related (i.e. homologous) to non extreme temperature living organism. To understand the structural and dynamics differences that allow these proteins to be functionally active at such extreme temperatures, we have studied three hemeglobins from the same subfamily (the truncated hemoglobins (trHb)), that belong to organisms that live in drastically different temperature conditions: very high (Thermobifida fusca), very low (Pseudoalteromonas haloplanktis), and moderate (Mycobacterium tuberculosis). In order to gain insight into the structural dynamics mechanims that allows extreme temperature adaptation we have peroformed Molecular Dynamics (MD) simulations of each trHb at two different temperatures, namely 300K and 360K. For each case we studied several general structural parameters that characterize the overall structure and dynamics as well as those key parameters that determine the O2 affinity for each case. Our results show that in T. fusca the estabilization of the O2 is more sensitive to the temperature’s change. This not happens in M. Tuberculosis and P. Haloplanktis, where the estabilization of the O2 not appear to be affected for the temperature.