This entry represents the guanylyltransferase component of the Iron-guanylylpyridinol (FeGP) cofactor biosynthesis protein HcgB [1]. This family of proteins with unknown function appears to be restricted to Methanobacteria.

1: Protein-pyridinol thioester precursor for biosynthesis of the organometallic acyl-iron ligand in [Fe]-hydrogenase cofactor. Fujishiro T, Kahnt J, Ermler U, Shima S; Nat Commun. 2015;6:6895. PMID:25882909

2: Towards artificial methanogenesis: biosynthesis of the [Fe]-hydrogenase cofactor\tand characterization of the semi-synthetic hydrogenase. Bai L, Fujishiro T, Huang G, Koch J, Takabayashi A, Yokono M, Tanaka A, Xu T, Hu X, Ermler U, Shima S; Faraday Discuss. 2017;198:37-58. PMID:28294213