BIOCHEMICAL AND PHYLOGENETIC CHARACTERIZATION OF THE DUTPASE FROM THEARCHAEAL VIRUS SIRV

The derived amino acid sequence from a 474-base pair open reading fram e in the genome of the Sulfolobus islandicus rod-shaped virus SIRV sho ws striking similarity to bacterial dCTP deaminases and to dUTPases fr om eukaryotes, bacteria, Poxviridae, and Retroviridae, The putative ge ne was expressed in Escherichia coli, and dUTPase activity of the reco mbinant enzyme was demonstrated by hydrolysis of dUTP to dUMP. Deamina tion of dCTP by the enzyme was not detected, Phylogenetic analysis bas ed on amino acid sequences of the characterized enzyme and its homolog ues showed that the dUTPase-encoding dut genes and the dCTP deaminase encoding dcd genes constitute a paralogous gene family, This report is the first identification and functional characterization of an archae al dUTPase and the first phylogeny derived for the dcd-dut gene family .