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Name help_outline
a menaquinone
Identifier
CHEBI:16374
(CAS: 11032-49-8)
help_outline
Charge
0
Formula
(C5H8)nC11H8O2
Search links
Involved in 47 reaction(s)
Find proteins in UniProtKB for this molecule
Form(s) in this reaction:
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Identifier: RHEA-COMP:9537Polymer name: a menaquinonePolymerization index help_outline nFormula C11H8O2(C5H8)nCharge (0)(0)nMol File for the polymer
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- Name help_outline succinate Identifier CHEBI:30031 (Beilstein: 1863859; CAS: 56-14-4) help_outline Charge -2 Formula C4H4O4 InChIKeyhelp_outline KDYFGRWQOYBRFD-UHFFFAOYSA-L SMILEShelp_outline [O-]C(=O)CCC([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 331 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
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Name help_outline
a menaquinol
Identifier
CHEBI:18151
Charge
0
Formula
C11H10O2(C5H8)n
Search links
Involved in 53 reaction(s)
Find proteins in UniProtKB for this molecule
Form(s) in this reaction:
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Identifier: RHEA-COMP:9539Polymer name: a menaquinolPolymerization index help_outline nFormula C11H10O2(C5H8)nCharge (0)(0)nMol File for the polymer
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- Name help_outline fumarate Identifier CHEBI:29806 (Beilstein: 1861276; CAS: 142-42-7) help_outline Charge -2 Formula C4H2O4 InChIKeyhelp_outline VZCYOOQTPOCHFL-OWOJBTEDSA-L SMILEShelp_outline [O-]C(=O)\C=C\C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 40 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:27834 | RHEA:27835 | RHEA:27836 | RHEA:27837 | |
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Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Related reactions help_outline
Specific form(s) of this reaction
More general form(s) of this reaction
Publications
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Structure of the Escherichia coli fumarate reductase respiratory complex.
Iverson T.M., Luna-Chavez C., Cecchini G., Rees D.C.
The integral membrane protein fumarate reductase catalyzes the final step of anaerobic respiration when fumarate is the terminal electron acceptor. The homologous enzyme succinate dehydrogenase also plays a prominent role in cellular energetics as a member of the Krebs cycle and as complex II of t ... >> More
The integral membrane protein fumarate reductase catalyzes the final step of anaerobic respiration when fumarate is the terminal electron acceptor. The homologous enzyme succinate dehydrogenase also plays a prominent role in cellular energetics as a member of the Krebs cycle and as complex II of the aerobic respiratory chain. Fumarate reductase consists of four subunits that contain a covalently linked flavin adenine dinucleotide, three different iron-sulfur clusters, and at least two quinones. The crystal structure of intact fumarate reductase has been solved at 3.3 angstrom resolution and demonstrates that the cofactors are arranged in a nearly linear manner from the membrane-bound quinone to the active site flavin. Although fumarate reductase is not associated with any proton-pumping function, the two quinones are positioned on opposite sides of the membrane in an arrangement similar to that of the Q-cycle organization observed for cytochrome bc1. << Less
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Crystallographic studies of the Escherichia coli quinol-fumarate reductase with inhibitors bound to the quinol-binding site.
Iverson T.M., Luna-Chavez C., Croal L.R., Cecchini G., Rees D.C.
The quinol-fumarate reductase (QFR) respiratory complex of Escherichia coli is a four-subunit integral-membrane complex that catalyzes the final step of anaerobic respiration when fumarate is the terminal electron acceptor. The membrane-soluble redox-active molecule menaquinol (MQH(2)) transfers e ... >> More
The quinol-fumarate reductase (QFR) respiratory complex of Escherichia coli is a four-subunit integral-membrane complex that catalyzes the final step of anaerobic respiration when fumarate is the terminal electron acceptor. The membrane-soluble redox-active molecule menaquinol (MQH(2)) transfers electrons to QFR by binding directly to the membrane-spanning region. The crystal structure of QFR contains two quinone species, presumably MQH(2), bound to the transmembrane-spanning region. The binding sites for the two quinone molecules are termed Q(P) and Q(D), indicating their positions proximal (Q(P)) or distal (Q(D)) to the site of fumarate reduction in the hydrophilic flavoprotein and iron-sulfur protein subunits. It has not been established whether both of these sites are mechanistically significant. Co-crystallization studies of the E. coli QFR with the known quinol-binding site inhibitors 2-heptyl-4-hydroxyquinoline-N-oxide and 2-[1-(p-chlorophenyl)ethyl] 4,6-dinitrophenol establish that both inhibitors block the binding of MQH(2) at the Q(P) site. In the structures with the inhibitor bound at Q(P), no density is observed at Q(D), which suggests that the occupancy of this site can vary and argues against a structurally obligatory role for quinol binding to Q(D). A comparison of the Q(P) site of the E. coli enzyme with quinone-binding sites in other respiratory enzymes shows that an acidic residue is structurally conserved. This acidic residue, Glu-C29, in the E. coli enzyme may act as a proton shuttle from the quinol during enzyme turnover. << Less