2ch1

Publication Abstract from PubMed

In Anopheles gambiae, the vector for the most deadly malaria parasite Plasmodium falciparum, xanthurenic acid (XA) plays a key role in parasite gametogenesis and fertility. In mosquitoes, XA is produced by transamination of 3-hydroxykynurenine (3-HK), a reaction that represents the main route to prevent the accumulation of the potentially toxic 3-HK excess. Interfering with XA metabolism in A. gambiae therefore appears an attractive avenue for the development of malaria transmission-blocking drugs and insecticides. We have determined the crystal structure of A. gambiae 3-HK transaminase in its pyridoxal 5'-phosphate form and in complex with a newly synthesized competitive enzyme inhibitor. Structural inspection of the enzyme active site reveals the key molecular determinants for ligand recognition and catalysis. Major contributions toward inhibitor binding are provided by a salt bridge between the inhibitor carboxylate and Arg-356 and by a remarkable hydrogen bond network involving the anthranilic moiety of the inhibitor and backbone atoms of residues Gly-25 and Asn-44. This study may be useful for the structure-based design of specific enzyme inhibitors of potential interest as antimalarial agents.

Crystal structure of the Anopheles gambiae 3-hydroxykynurenine transaminase.,Rossi F, Garavaglia S, Giovenzana GB, Arca B, Li J, Rizzi M Proc Natl Acad Sci U S A. 2006 Apr 11;103(15):5711-6. Epub 2006 Apr 3. PMID:16585514^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.