The parasitic protozoon Trichomonas vaginalis is the pathogen of trichomoniasis， the most common non-viral， sexually transmitted disease in humans. Inositol phosphates function in the pathomechanisms of a number of human pathogenic protozoa. Recent findings point to a role of inositol phosphates in T. vaginalis' adaption to oxygen exposure during change of host. Six inositol phosphate kinase genes (tvip6k1-4， tvipk1-2) were identified in the T. vaginalis genome by us all coding for proteins containing canonical sequence motifs of the major group of animal inositol phosphate kinases (PDKG， SSLL， DFG/A). When characterizing the purified protein product of tvip6k1， we discovered that the major activity... More
The parasitic protozoon Trichomonas vaginalis is the pathogen of trichomoniasis， the most common non-viral， sexually transmitted disease in humans. Inositol phosphates function in the pathomechanisms of a number of human pathogenic protozoa. Recent findings point to a role of inositol phosphates in T. vaginalis' adaption to oxygen exposure during change of host. Six inositol phosphate kinase genes (tvip6k1-4， tvipk1-2) were identified in the T. vaginalis genome by us all coding for proteins containing canonical sequence motifs of the major group of animal inositol phosphate kinases (PDKG， SSLL， DFG/A). When characterizing the purified protein product of tvip6k1， we discovered that the major activity of the highly active enzyme (?2?μmol/min/mg) is a conversion of InsP to 6PP-InsP and not 5PP-InsP as by animal isoforms. Thus TvIP6K1 is a novel IP6-6K. The enzyme also converts Ins(1，3，4，5，6)P to products pyrophosphorylated both at 6- and 4-phosphate still having a free 5-hydroxyl. In addition， the enzyme has a minor selectivity to phosphorylate the 3-OH in Ins(1，2，4，5)P and Ins(1，2，4，5，6)P. To present knowledge this novel enzyme is restricted to protozoa. Since its structure is predicted to be distinctly different from animal IP6K (IP6-5K) forms， TvIP6-6K may become a promising target to search for novel trichomoniasis specific drugs.
