tailieunhanh - Báo cáo khoa học: Crystal structures of Aedes aegypti kynurenine aminotransferase

Aedes aegyptikynurenine aminotransferase (AeKAT) catalyzes the irrevers-ible transamination of kynurenine to kynurenic acid, the natural antagonist of NMDA and 7-nicotinic acetycholine receptors. Here, we report the crys-tal structure of AeKAT in its PMP and PLP forms at and A ˚ , respectively. The structure was solved by a combination of single-wave-length anomalous dispersion and molecular replacement approaches. | iFEBS Journal Crystal structures of Aedes aegypti kynurenine aminotransferase Qian Han1 z Yi Gui Gao1 2 z Howard Robinson3 Haizhen Ding1 Scott Wilson2 and Jianyong Li1 1 Department of Pathobiology University of Illinois Urbana IL USA 2 Schoolof ChemicalSciences University of Illinois Urbana IL USA 3 Biology Department Brookhaven NationalLaboratory Upton NY USA Keywords aminotransferase crystal structure kynurenic acid kynurenine aminotransferase mosquito Correspondence J. Li Department of Pathobiology University of Illinois 2001 South Lincoln Avenue Urbana IL 61802 USA Fax 217 2447421 Tel 217 244-3913 E-mail jli2@ Qian Han and Yi Gui Gao contributed equally to this work. Note The atomic coordinates and structure factors PDB codes 1YIZ and 1YIY have been deposited in the Protein Data Bank Research Collaborator for StructuralBioin-formatics Rutgers University New Brunswick NJ USA http . Aedes aegypti kynurenine aminotransferase AeKAT catalyzes the irreversible transamination of kynurenine to kynurenic acid the natural antagonist of NMDA and 7-nicotinic acetycholine receptors. Here we report the crystal structure of AeKAT in its PMP and PLP forms at and A respectively. The structure was solved by a combination of single-wavelength anomalous dispersion and molecular replacement approaches. The initial search model in the molecular replacement method was built with the result of single-wavelength anomalous dispersion data from the Br-AeKAT crystal in combination with homology modeling. The solved structure shows that the enzyme is a homodimer and that the two subunits are stabilized by a number of hydrogen bonds salts bridges and hydrophobic interactions. Each subunit is divided into an N-terminal arm and small and large domains. Based on its folding the enzyme belongs to the prototypical fold type aminotransferase subgroup I. The three-dimensional structure shows a strictly conserved PLP-phosphate binding cup featuring PLP-dependent .