H2-forming N5,N10-methylenetetrahydromethanopterin dehydrogenase, C-terminal (IPR004889)

Short name: HMD_C

Overlapping homologous superfamilies

Domain relationships



This entry represents the C-terminal domain of H2-forming N5,N10-methylene-tetrahydromethanopterin dehydrogenases. The N(5),N(10)-methylenetetrahydromethanopterin dehydrogenase system of methanogenic archaea is composed of H2-forming methylenetetrahydromethanopterin dehydrogenase (Hmd, represented by this entry) and F420-dependent methylenetetrahydromethanopterin dehydrogenase (IPR002844) [PMID: 8215796, PMID: 9151968]. Hmd is an iron-sulphur-cluster-free enzyme that contains an intrinsic CO ligand bound to iron [PMID: 15506791]. This domain is found at the C terminus of two distinct subgroups: one has been experimentally characterised as H2-forming N(5),N(10)-methenyltetrahydromethanopterin dehydrogenase (Hmd or HmdI), and the other one contains isozymes that have not been experimentally characterised (HmdII and HmdIII). Because all three isozyme forms are present in each of the corresponding sequenced genomes, it has been suggested that HmdII and HmdIII may not exhibit Hmd activity and may have a different biological function [PMID: 11081790]. Based on on its ability to bind to aminoacyl-tRNA synthetases and tRNA, a role for HmdII has been proposed as a regulator of protein synthesis that senses intracellular methylene-H4 MPT concentration [PMID: 26094576].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.