TupA and ModA: Characterization of tungstate and molybdate binding proteins from Desulfovibrio alaskensis G20.

R. CORREIA CORDEIRO; A.R. OTRELO-CARDOSO; R.R. NAIR; M.A.S. CORREIA; T. SANTOS-SILVA; M.G. RIVAS

Hamburgo

Conferencia; 15th International Conference on the Crystallization of Biological Macromolecules.; 2014

Molybdenum (Mo) and tungsten (W) are chemically analogous elements that are found in the environment. In biological systems, Mo and W are incorporated into the active site of enzymes through binding to a pyranopterin moiety. The Mo and W enzymes have an important physiological role, including the catalysis of some main reactions in the metabolism of carbon, nitrogen and sulfur.3These elements are incorporated into the cell through specific transport systems, one of them known as TupABC. This is composed of a protein located in periplasm (TupA), a membrane protein (TupB) and a protein confined in the cytoplasm (TupC) responsible for the hydrolysis of ATP, thus generating the energy needed to transport the oxyanions to the cell. In order to understand the binding mode and the metal specificity of the protein, site directed mutagenesis has been carried out and three different mutants of TupA have been designed, substituting arginine 118 to a lysine (R118K), a glutamine (R118Q) and a glutamate (R118E).