Cell cycle regulation and novel structural features of thymidine kinase, an essential enzyme in Trypanosoma brucei

• DOI: 10.1111/mmi.13467
• Publication Date: 2016-07-18T08:33:19Z
• Authors: Maria Valente; Jennifer Timm; Víctor M. Castill...; Luis M. Ruiz‐Pérez; Tom Balzarini; Joanne E. Nettleship; Louise E. Bird; Heather Rada; Keith S. Wilson; Dolores González‐...
• Keywords: Thymidine kinase; Thymidine

Thymidine kinase (TK) is a key enzyme in the pyrimidine salvage pathway which catalyzes transfer of γ-phosphate ATP to 2'-deoxythymidine (dThd) forming thymidine monophosphate (dTMP). Unlike other type II TKs, Trypanosoma brucei (TbTK) tandem protein with two TK homolog domains only C-terminal one active. In this study, we establish that TbTK essential for parasite viability and cell cycle progression, independently extracellular concentrations. We show expression regulated depletion leads strongly diminished dTTP pools DNA damage indicating intracellular dThd be an intermediate metabolite synthesis thymine-derived nucleotides. addition, report X-ray structure catalytically active domain complex dTMP at resolutions up 2.2 Å. spite high conservation site residues, structures reveal widened cavity near nucleobase moiety compared human enzyme. Our findings support as crucial homeostasis identify structural differences within could exploited process rational drug design.