Archaea utilize the mevalonate (MVA) pathway for the biosynthesis of the essential isoprenoid building blocks, isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). Genomic analysis failed to identify homologues for several MVA pathway enzymes in most of the archaeal strains. A recently identified kinase that resides in proximity to genes for other MVA pathway enzymes was found to phosphorylate proficiently isopentenyl phosphate (IP) to IPP, suggesting an alternative route for the MVA pathway in Archaea. This IP kinase represents a potentially powerful tool for radiolabeling of IPP and its analogs.;In this thesis, IP kinases from two archaeal strains, Methanothermobacter thermautotrophicus and Thermoplasma acidophilum, have been cloned and kinetically characterized. Their substrate specificities were evaluated using analogs of IP, isopentenyl thiophosphate (ISP), dimethylallyl phosphate (DMAP), n-butyl phosphate (AP), 3-butenyl phosphate (EP), and geranyl phosphate (GP) as the prelude for future protein engineering studies.
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