title: The 6-phosphogluconate dehydrogenase of Leishmania (Leishmania) mexicana: gene characterization and protein structure prediction.
abstract: 6-Phosphogluconate dehydrogenase (6PGDH) is a key enzyme of the oxidative branch involved in the generation of NADPH and ribulose 5-phosphate. In the present work, we describe the cloning, sequencing and characterization of a 6PGDH gene from Leishmania (Leishmania) mexicana. The gene encodes a polypeptide chain of 479 amino acid residues with a predicted molecular mass of 52 kDa and a pI of 5.77. The recombinant protein possesses a dimeric quaternary structure and displays kinetic parameter values intermediate between those reported for Trypanosoma brucei and T. cruzi with apparent K(m) values of 6.93 and 5.2 μM for 6PG and NADP(+), respectively. The three-dimensional structure of the enzymes of Leishmania and T. cruzi were modelled from their amino acid sequence using the crystal structure of the enzyme of T. brucei as template. The amino acid residues located in the 6PGDH C-terminal region, which are known to participate in the salt bridges maintaining the protein dimeric structure, differed significantly among the enzymes of Leishmania, T. cruzi, and T. brucei. Our results strongly suggest that 6PGDH can be selected as a potential target for the development of new therapeutic drugs in order to improve existing chemotherapeutic treatments against these parasites.
authors.affiliation: Laboratorio de Bioquímica y Biología Molecular de Parásitos, Instituto de Biología Experimental (IBE), Facultad de Ciencias, Universidad Central de Venezuela, Caracas, Venezuela.
authors.forename: Deyanira
authors.initials: D
authors.lastname: González
authors.forename: José Luis
authors.initials: JL
authors.lastname: Pérez
authors.forename: María Luisa
authors.initials: ML
authors.lastname: Serrano
authors.forename: Mariana
authors.initials: M
authors.lastname: Igoillo-Esteve
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Cazzulo
authors.forename: Michael P
authors.initials: MP
authors.lastname: Barrett
authors.forename: José
authors.initials: J
authors.lastname: Bubis
authors.forename: Alexis
authors.initials: A
authors.lastname: Mendoza-León
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D007894:Leishmania mexicana / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010734:Phosphogluconate Dehydrogenase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D011994:Recombinant Proteins; D010734:Phosphogluconate Dehydrogenase