Methanofuran

Structure of the methanofurans

Methanofuran describes a family of chemical compounds found in methanogenic archaea.^[1] These species feature a 2-aminomethylfuran linked to phenoxy group. At least three different end groups are recognized: R = tricarboxyheptanoyl (methanofuran), glutamyl-glutamyl (methanofuran b), tricarboxy-2-hydroxyheptanoyl (methanofuran c, see picture).

Formylation of MFR

Methanofuran converts to formylmethanofuran in an early stage of methanogenesis. The enzyme formylmethanofuran dehydrogenase (EC: 1.2.99.5) formylates methanofuran using CO
2, the primary C1 source in methanogenesis.^[2]

Deformylation of MFR

The enzyme formylmethanofuran:tetrahydromethanopterin formyltransferase catalyzes the transfer of the formyl group from formylmethanofuran to N5 on tetrahydromethanopterin, H
4MPT. This enzyme has been crystallized; it contains no prosthetic group.^[3]

References

1. Thauer RK (September 1998). "Biochemistry of methanogenesis: a tribute to Marjory Stephenson. 1998 Marjory Stephenson Prize Lecture". Microbiology. 144 (Pt 9): 2377–406. doi:10.1099/00221287-144-9-2377. PMID 9782487.
2. Vorholt JA, Thauer RK (September 1997). "The active species of CO
   2 utilized by formylmethanofuran dehydrogenase from methanogenic Archaea". Eur. J. Biochem. 248 (3): 919–24. doi:10.1111/j.1432-1033.1997.00919.x. PMID 9342247.
3. Acharya P, Warkentin E, Ermler U, Thauer RK, Shima S (March 2006). "The structure of formylmethanofuran: tetrahydromethanopterin formyltransferase in complex with its coenzymes". J. Mol. Biol. 357 (3): 870–9. doi:10.1016/j.jmb.2006.01.015. PMID 16466742.