Biochemical Characterization of Thymidine Monophosphate Kinase from white Spot Syndrome Virus: A Functional Domain from the Viral ORF454

Nucleotide phosphorylation is a key step towards DNA replication and during viral infections the maintenance of the nucleotide triphosphates pool is required. Deoxythymidine triphosphate (dTTP) is the unique nucleotide that is produced either by de novo or salvage pathways. Thymidine monophosphate kinase (TMK) is the enzyme that phosphorylates deoxythymidine monophosphate (dTMP) using adenosine triphosphate (ATP) as a phosphate group donor in presence of Mg2+ yielding deoxythymidine diphosphate (dTDP) and adenosine diphosphate. The TMK region of the WSSV TK-TMK chimeric protein was overexpressed and purified. This recombinant protein had TMK activity, this is that dTMP was phosphorylated to dTDP and we found that the dimeric state of the protein was the functional and a theoretical structural model was built as such. Future work will focus towards a structural characterization as an antiviral target.