A QM/MM study of the autophosphorylation of the catalytic domain of CopA

SABECKIS, LURDES; ROMAN, ERNESTO A.; GONZÁLEZ FLECHA, F. LUIS; MARIANO C. GONZÁLEZ LEBRERO

Villa Carlos Paz, Córdoba

Congreso; XLI Reunión anual de la Sociedad Argentina de Biofísica.; 2013

CopA is the thermophilic Cu+-P-type ATPase from Archaeoglobus fulgidus. This protein couples the energy of ATP hydrolysis to Cu+ translocation across cellular membranes. In the reaction cycle it is generated a phosphorylated metastable intermediate that gives the name of P-ATPases to this family of proteins. The ATP hydrolysis takes place within an intracellular domain which is composed by two subdomains: a nucleotide binding or N-domain and a phosphorylation or P-domain. This domain hydrolyze ATP and inorganic phosphate esters at high temperatures even when purified without the rest of CopA. The aim of this work is to study the active site dynamics and the autophosphorylation reaction of this domain using computational simulation techniques. In particular it is studied the protonation of D424 (the phosphate acceptor), as well as the proton transfer of the K600 to the reactive phosphate, and its influence in this reaction. For this, classical and hybrid QM/MM simulations techniques were performed using the AMBER simulation set of programs, and a proper developed code for the calculus and the quantum subsystem, based on Density Functional Theory (DFT) and the PBE functional. This code was modified for the employment of Graphics processing units (GPUs) in its most demanding parts.