The family represents the N-terminal hydrolase domain of HypX protein. HypX is involved in the maturation process of active [NiFe] hydrogenase. [NiFe] hydrogenases function in H2 metabolism in a variety of microorganisms, enabling them to use H2 as a source of reducing equivalent under aerobic and anaerobic conditions. [NiFe] hydrogenases consist of a large and a small subunit. The large subunit contains [NiFe] active site, which is synthesized as a precursor without the [NiFe] active site. This precursor then undergoes a complex post-translational maturation process that requires the presence of a number of accessory proteins. HypX has been shown to be involved in this maturation process and have been proposed to participate in the generation and transport of the CO and CN ligands. However, HypX is not present in all hydrogen-metabolizing bacteria. Furthermore, hypX deletion mutants have a reduced but detectable level of hydrogenase activity. Thus, HypX might not be a determining factor in the matur ation process. Members of this group have an N-terminal formyl transferase domain and a C-terminal enoyl-CoA hydratase/isomerase domain.
Jiyao W et al.(2023). "The conserved domain database in 2023.",