A novel 6-pyrophosphorylating IP6 kinase (IP6-6K) discovered in the protozoon Trichomonas vaginalis

Publication date: Available online 26 December 2018Source: Molecular and Biochemical ParasitologyAuthor(s): Torsten Wundenberg, Marcus M. Nalaskowski, Benjamin Löser, Werner Fanick, Thomas Hackl, Ursula Fürnkranz, Christoph Rehbach, Hongying Lin, Georg W. MayrAbstractThe 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 (P-D-K-G, SSLL, DFG/A). When characterizing the purified protein product of tvip6k-1, we discovered that the major activity of the highly active enzyme (˜2 µmol/min/mg) is a conversion of InsP6 to 6-PP-InsP5 and not 5-PP-InsP5 as by animal isoforms. Thus TvIP6 K1 is a novel IP6-6 K. The enzyme also converts Ins(1,3,4,5,6)P5 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)P4 and Ins(1,2,4,5,6)P5. To present knowledge this novel enzyme is restricted to protozoa. Since its structure is predicted to...
Source: Molecular and Biochemical Parasitology - Category: Parasitology Source Type: research