Identification of Babesia bovis L-lactate dehydrogenase as a potential chemotherapeutical target against bovine babesiosis.
In this study, we characterized a novel Babesia bovis cDNA clone obtained by immunoscreening the cDNA expression phage library with B. bovis-infected bovine serum. The genetic analyses showed that it contained an open reading frame of 993 bp, which was considered to encode B. bovis L-lactate dehydrogenase (BbLDH: E.C. 1.1.1.27) because of the strikingly high amino acid identities of its gene product to the LDHs of Plasmodium falciparum and Toxoplasma gondii. Immunological analyses with the anti-recombinant BbLDH mouse serum showed that 36 kDa of the native BbLDH was expressed not only in the cytoplasm of intra- and extraerythrocytic parasites but also along the membrane of infected erythrocytes. The kinetic properties of recombinant BbLDH proved a certain enzymatic activity of LDH, and the activity was significantly inhibited by the addition of gossypol, a competitive inhibitor of protozoan LDHs. Moreover, 100 microM of the gossypol irretrievably arrested the in vitro growth of B. bovis. The results demonstrated that BbLDH provides a suitable drug target for the design of novel babesial chemotherapeutics.
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
Sabine
S
Bork
Masashi
M
Okamura
Suthisak
S
Boonchit
Haruyuki
H
Hirata
Naoaki
N
Yokoyama
Ikuo
I
Igarashi
D000595:Amino Acid Sequence; D000818:Animals; D000913:Antibodies, Protozoan; D016793:Babesia bovis / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D001404:Babesiosis / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy* / Q000469:parasitology; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D016054:DNA, Protozoan / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D017125:Genes, Protozoan; D006072:Gossypol / Q000494:pharmacology; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data
D000913:Antibodies, Protozoan; D018076:DNA, Complementary; D016054:DNA, Protozoan; D004791:Enzyme Inhibitors; D007770:L-Lactate Dehydrogenase; D006072:Gossypol