Tetrahydromethanopterin
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Tetrahydromethanopterin".

Tetrahydromethanopterin
Identifiers
CAS number
PubChem	5459995
Properties
Molecular formula	C30H45N6O16P
Molar mass	776.682661
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Tetrahydromethanopterin, abbreviated H₄MPT, is a coenzyme in methanogenesis. It is the carrier of the C1 group as it is reduced to the methyl level, before transferring to the coenzyme M.^[1]

Tetrahydrosarcinapterin (H₄SPT) is a modified form of H₄MPT, wherein a glutamyl group linked to the 2-hydroxyglutaric acid terminus.

H₄MPT is the main platform for C1 transformations

N-Formylmethanofuran donates the C1 group to the N5 site of the pterin to give the formylH₄MPT.^[2] The formyl group subsequently condenses intramolecularly to give methenylH₄MPT⁺, which is then reduced to methyleneH₄MPT.^[3] MethyleneMPT is subsequently converted, using H₂F₄₂₀ as the electron source, to methylH₄MPT, catalyzed by F₄₂₀-dependent methylene-H₄MPT reductase. MethylH₄MPT is the methyl donor to coenzyme M, a conversion mediated by methyl-H₄MPT:coenzyme M methyl-transferase.^[1]

Comparison with tetrahydrofolate

H₄MPT is related to the better known tetrahydrofolate (H₄F). The differences are indicated in red and blue in the figure. The most important difference between H₄MPT and H₄F is that H₄F has an electron-withdrawing carbonyl group on the phenyl ring. As a consequence, methenyl-H₄MPT is more difficult to reduce than methenyl-H₄F. Reduction is effected by a so-called Iron-sulfur cluster free hydrogenase.^[3] The cumbersome name distinguishes this hydrogenase from the so-called Fe-only hydrogenases that do contain Fe-S cluster.

References

1. ^ ^{a b} Thauer, R. K., "Biochemistry of Methanogenesis: a tribute to Marjory Stephenson", Microbiology, 1998, 144, 2377-2406.
2. ^ Acharya, P.; Warkentin, E.; Ermler, U.; Thauer, R. K.; Shima, S., "The Structure of Formylmethanofuran:Tetrahydromethanopterin Formyltransferase in Complex with its Coenzymes", Journal of Molecular Biology, 2006, volume 357, pages 870-879.
3. ^ ^{a b} Korbas, M.; Vogt, S.; Meyer-Klaucke, W.; Bill, E.; Lyon, E. J.; Thauer, R. K. and Shima, S., "The Iron-Sulfur Cluster-free Hydrogenase (Hmd) Is a Metalloenzyme with a Novel Iron Binding Motif", Journal of Biological Chemistry, 2006, volume 281, pages 30804-30813.

This biochemistry article is a stub. You can help Wikipedia by expanding it.