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. A few family members contain additional domains, like a C-terminal peptidase S24-like domain.
Jiyao W et al.(2023). "The conserved domain database in 2023.",