| Tetrahydromethanopterin | |
|---|---|
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| Identifiers | |
| PubChem | |
| 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 references |
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Tetrahydromethanopterin (THMPT, 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 (THSPT, H4SPT) is a modified form of THMPT, wherein a glutamyl group linked to the 2-hydroxyglutaric acid terminus.
THMPT is the main platform for C1 transformations
N-Formylmethanofuran donates the C1 group to the N5 site of the pterin to give the formyl- THMPT.[2] The formyl group subsequently condenses intramolecularly to give methenyl- THMPT+, which is then reduced to methylene- THMPT.[3] Methylene- MPT is subsequently converted, using coenzyme F420 as the electron source, to methyl- THMPT, catalyzed by F420-dependent methylene- THMPT reductase. Methyl- THMPT is the methyl donor to coenzyme M, a conversion mediated by methyl- THMPT:coenzyme M methyl-transferase.[1]
Comparison with tetrahydrofolic acid
THMPT is related to the better known tetrahydrofolic acid (THFA, H4FA). The differences are indicated in red and blue in the figure. The most important difference between THMPT and THFA is that THFA has an electron-withdrawing carbonyl group on the phenyl ring. As a consequence, methenyl- THMPT is more difficult to reduce than methenyl- THFA. 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
- ^ a b Thauer, R. K., "Biochemistry of Methanogenesis: a tribute to Marjory Stephenson", Microbiology, 1998, 144, 2377-2406.
- ^ 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.
- ^ 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.
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