N-terminal putative catalytic domain of uncharacterized prokaryotic and archeal HKD family nucleases fused to a DEAD/DEAH box helicase domain
N-terminal putative catalytic domain of uncharacterized prokaryotic and archeal HKD family nucleases fused to a DEAD/DEAH box helicase domain. All members of this subfamily are uncharacterized. Other characterized members of the superfamily that have a related domain architecture ( containing a DEAD/DEAH box helicase domain), include the DNA/RNA helicase superfamily II (SF2) and Res-subunit of type III restriction endonucleases. In addition to the helicase-like region, members of this subfamily also contain one copy of the conserved HKD motif (H-x-K-x(4)-D, where x represents any amino acid residue) in the N-terminal putative catalytic domain. The HKD motif characterizes the phospholipase D (PLD, EC 3.1.4.4) superfamily.
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