Homologous Superfamily

EutN/Ccml superfamily (IPR036677)

Short name: EutN_CcmL_sf

Overlapping entries


The ethanolamine utilization protein EutN is involved in the cobalamin-dependent degradation of ethanolamine [PMID: 10464203]. The crystal structure of EutN contains a central five-stranded beta-barrel, with an alpha-helix at the open end of this barrel (PDB: 2HD3). The structure also contains three additional beta-strands, which help the formation of a tight hexamer, with a hole in the centre. This suggests that EutN forms a pore, with an opening of 26 Amstrong in diameter on one face and 14 Amstrong on the other face [PMID: 17588214].

Beside the Escherichia coli ethanolamine utilization protein EutN and the Synechocystis sp. carboxysome (beta-type) structural protein CcmL, this family also includes alpha-type carboxysome structural proteins CsoS4A and CsoS4B (previously known as OrfA and OrfB), propanediol utilizationprotein PduN, and some hypothetical homologous of various bacterial microcompartments. The carboxysome, a polyhedral organelle, participates in carbon fixation by sequestering enzymes. It is the prototypical bacterial microcompartment. Its enzymatic components, ribulose bisphosphate carboxylase/oxygenase(RuBisCO) and carbonic anhydrase (CA), are surrounded by a polyhedral protein shell. Similarly, the ethanolamine utilization (eut) microcompartment, and the 1,2-propanediol utilization (pdu) microcompartment encapsulate the enzymes necessary for the process of cobalamin-dependent ethanolamine degradation, and coenzyme B12-dependent degradation of 1,2-propanediol, respectively, within its polyhedral protein shells. It is interesting that both carboxysome structural proteins CcmL and CsoS4A assemble as pentamers in the crystal structures, which might constitute the twelve pentameric vertices of a regular icosahedral carboxysome. However, the reported EutN structure is hexameric rather than pentameric. The absence of pentamers in Eut microcompartments might lead to less-regular icosahedral shell shapes. Due to the lack of structure evidence, the functional roles of the CsoS4A adjacent paralog, CsoS4B, and propanediol utilization protein PduN are not yet clear [PMID: 10464203, PMID: 19177356, PMID: 18248510, PMID: 17511640, PMID: 18258595, PMID: 18937343, PMID: 17578868, PMID: 18758469, PMID: 16525780, PMID: 18679172, PMID: 15862091, PMID: 12554704, PMID: 11722879, PMID: 18974784, PMID: 17897412, PMID: 18332146, PMID: 18292340, PMID: 17993516, PMID: 2656649, PMID: 17669419, PMID: 3045078, PMID: 4127632, PMID: 4355679, PMID: 7868611, PMID: 7934888, PMID: 8491708, PMID: 9245772, PMID: 9891798, PMID: 12520366, PMID: 12923081, PMID: 14729686, PMID: 15516577, PMID: 16081736, PMID: 16385071, PMID: 16585748, PMID: 17028023, PMID: 179979, PMID: 190964].

This entry represents a superfamily of related bacterial proteins with roles in ethanolamine and carbon dioxide metabolism. The structure of these domains has a close or partly open barrel fold and a greek-key topology.

Contributing signatures

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