Biochemical characterization and crystallization of recombinant 3-phosphoglycerate kinase of Plasmodium falciparum.

Human malaria parasite Plasmodium falciparum depends largely on glycolytic pathway for energy metabolism during the intraerythrocytic life stage. Therefore, enzymes of the glycolytic pathway could offer potential drug targets provided novel biochemical and/or structural features of the parasitic enzymes, which distinguish them from the host counterpart, could be identified. 3-Phosphoglycerate kinase (EC 2.7.2.3) catalyzes an important phosphorylation step leading to the production of ATP in the glycolytic pathway. We have expressed recombinant 3-phosphoglycerate kinase of P. falciparum in Escherichia coli. The recombinant protein purified from the soluble fraction of E. coli is enzymatically active. The apparent K(m) values determined for adenosine triphosphate (ATP) and 3-phosphoglycerate (3-PGA) are 0.63 and 0.52 mM, respectively. The enzyme activity was temperature-sensitive. Suramin was found to inhibit the recombinant enzyme with an IC(50) value of 7 microM. We have crystallized the enzyme form in hexagonal space group P6(1)22 (or its enantiomorphic space group) with unit cell parameters a=b=130.7, c=263.9 A. Native data have been collected at 3.0-A resolution.