title: Mechanistic binding insights for 1-deoxy-D-Xylulose-5-Phosphate synthase, the enzyme catalyzing the first reaction of isoprenoid biosynthesis in the malaria-causing protists, Plasmodium falciparum and Plasmodium vivax.
abstract: We have successfully truncated and recombinantly-expressed 1-deoxy-D-xylulose-5-phosphate synthase (DXS) from both Plasmodium vivax and Plasmodium falciparum. We elucidated the order of substrate binding for both of these ThDP-dependent enzymes using steady-state kinetic analyses, dead-end inhibition, and intrinsic tryptophan fluorescence titrations. Both enzymes adhere to a random sequential mechanism with respect to binding of both substrates: pyruvate and D-glyceraldehyde-3-phosphate. These findings are in contrast to other ThDP-dependent enzymes, which exhibit classical ordered and/or ping-pong kinetic mechanisms. A better understanding of the kinetic mechanism for these two Plasmodial enzymes could aid in the development of novel DXS-specific inhibitors that might prove useful in treatment of malaria.
authors.affiliation: Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Battistini
authors.affiliation: Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Shoji
authors.affiliation: Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA.
authors.forename: Sumit
authors.initials: S
authors.lastname: Handa
authors.affiliation: College of Medicine and Molecular Medicine, University of South Florida Health, 12901 Bruce B. Downs Blvd., MDC 3529, Tampa, FL 33612, USA.
authors.forename: Leonid
authors.initials: L
authors.lastname: Breydo
authors.affiliation: Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA. Electronic address: merkler@usf.edu.
authors.forename: David J
authors.initials: DJ
authors.lastname: Merkler
mesh_terms: D000595:Amino Acid Sequence; D020134:Catalytic Domain; D003001:Cloning, Molecular; D005986:Glyceraldehyde 3-Phosphate / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000201:enzymology*; D010966:Plasmodium vivax / Q000201:enzymology*; D015800:Protozoan Proteins / Q000378:metabolism*; D019289:Pyruvic Acid / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D014166:Transferases / Q000378:metabolism*
chemical_list: D015800:Protozoan Proteins; D011994:Recombinant Proteins; D005986:Glyceraldehyde 3-Phosphate; D019289:Pyruvic Acid; D014166:Transferases; C109461:deoxyxylulose-5-phosphate synthase
keywords: 1-Deoxy-d-xylulose-5-phosphate synthase; Isoprenoids; Malaria; Methylerythritol phosphate pathway; Plasmodium falciparum; Plasmodium vivax