This domain is often found adjacent to the DHH domain Pfam:PF01368 and is called DHHA2 for DHH associated domain. This domain is diagnostic of DHH subfamily 2 members [1]. The domain is about 120 residues long and contains a conserved DXK motif at its amino terminus.

1: A novel family of predicted phosphoesterases includes Drosophila prune protein and bacterial RecJ exonuclease. Aravind L, Koonin EV; Trends Biochem Sci 1998;23:17-19. PMID:9478130