An Archaeal 2-Deoxyribose 5-phosphate Aldolase that Exhibits Closer Homology to Bacteria rather than Archaea

This study reports on primary structure comparison and some enzymatic characterization of 2-deoxyribose 5-phosphate aldolase from the hyperthermophilic archaeon, Thermococcus kodakaraensis KOD1 (Tk-DeoC). The Tk-DeoC exhibited a significant closer homology to bacterial 2-deoxyribose S-phosphate aldolases (DeoC) than those of archaeal counterparts. Recombinant Tk-DeoC catalyzed the conversion of 2-deoxyribose S-phosphate to acetaldehyde and glyceraldehyde 3-phosphate with a highest activity at 95 C and the pH optimum of 4.0. In T. kodakaraensis transcription of deoC was readily detectable and the corresponding DeoC activity was measurable in the cell-free extracts, indicating the constitutive expression of deoC in T. kodakaraensis cells. However, in contrast to the finding in bacteria where DeoC, together with DeoA, DeoB and DeoD, participate in the catabolism of exogenous DNA and presence of nucleotides in the growth medium induces these genes, supplementation of DNA to the growth medium showed no detectable induction of deoC transcription.