This family contains HypE (or HupE), a protein required for expression of catalytically active hydrogenase in many systems. It appears to be an accessory protein involved in maturation rather than a regulatory protein involved in expression. HypE shows considerable homology to the thiamine-monophosphate kinase ThiL (TIGR01379) and other enzymes.
Jiyao W et al.(2023). "The conserved domain database in 2023.",