Chemistry:Coenzyme B
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| IUPAC name
2-[(7-mercapto-1-oxoheptyl)amino]-3-phosphonooxybutanoic acid
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| Properties | |
| C11H22NO7PS | |
| Molar mass | 343.333641 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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| Infobox references | |
Coenzyme B is a coenzyme required for redox reactions in methanogens. The full chemical name of coenzyme B is 7-mercaptoheptanoylthreoninephosphate.[1] The molecule contains a thiol, which is its principal site of reaction.
Coenzyme B reacts with 2-methylthioethanesulfonate (methyl-Coenzyme M, abbreviated CH3–S–CoM), to release methane in methanogenesis:[2]
- CH3–S–CoM + HS–CoB → CH4 + CoB–S–S–CoM
This conversion is catalyzed by the enzyme methyl coenzyme M reductase, which contains cofactor F430 as the prosthetic group.
A related conversion that utilizes both HS-CoB and HS-CoM is the reduction of fumarate to succinate, catalyzed by fumarate reductase:[3]
- HS–CoM + HS–CoB + −O2CCH=CHCO−2 → −O2CCH2–CH2CO−2 + CoB–S–S–CoM
Importance of Coenzyme B in Methanogenesis
Coenzyme B is an important component in the terminal step of methane biogenesis.[4] It acts as a two electron-donor to reduce coenzyme M (methyl-coenzyme) into two molecules a methane and a heterodisulfide.[5] Two separate experiment that were performed, one with coenzyme B and other without coenzyme B, indicated that using coenzyme B before the formation of the methane molecule, results in a more efficient and consistent bond cleavage.[6]
References
- ↑ "Structure of component B (7-mercaptoheptanoylthreonine phosphate) of the methylcoenzyme M methylreductase system of Methanobacterium thermoautotrophicum". Proceedings of the National Academy of Sciences 83 (12): 4238–42. 1986. doi:10.1073/pnas.83.12.4238. PMID 3086878. Bibcode: 1986PNAS...83.4238N.
- ↑ 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.
- ↑ "Thiol:fumarate reductase (Tfr) from Methanobacterium thermoautotrophicum—identification of the catalytic sites for fumarate reduction and thiol oxidation". European Journal of Biochemistry 253 (1): 292–9. April 1998. doi:10.1046/j.1432-1327.1998.2530292.x. PMID 9578488.
- ↑ Dey, Mishtu; Li, Xianghui; Kunz, Ryan C; Ragsdale, Stephen W (2010-12-22). "Detection of Organometallic and Radical Intermediates in the Catalytic Mechanism of Methyl-Coenzyme M Reductase Using the Natural Substrate Methyl-Coenzyme M and a Coenzyme B Substrate Analogue". Biochemistry 49 (51): 10902–10911. doi:10.1021/bi101562m. PMID 21090696. https://pubs-acs-org.hunter.cuny.edu/doi/abs/10.1021/bi101562m.[yes|permanent dead link|dead link}}]
- ↑ Cedervall, Peder E; Dey, Mishtu; Pearson, Arwen R; Ragsdale, Stephen W; Wilmot, Carrie M (2010-07-22). "Structural Insight into Methyl-Coenzyme M Reductase Chemistry Using Coenzyme B Analogues". Biochemistry 49 (35): 7683–7693. doi:10.1021/bi100458d. PMID 20707311.
- ↑ Horng, Yih-Chern; Becker, Donald F; Ragsdale, Stephen W (2001-10-30). "Mechanistic Studies of Methane Biogenesis by Methyl-Coenzyme M Reductase: Evidence that Coenzyme B Participates in Cleaving the C−S Bond of Methyl-Coenzyme M". Biochemistry 40 (43): 12875–12885. doi:10.1021/bi011196y. PMID 11669624. https://pubs-acs-org.hunter.cuny.edu/doi/abs/10.1021/bi011196y.[yes|permanent dead link|dead link}}]
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