Sandbox Reserved 496: Difference between revisions

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'''β subunit reactions'''

C-cluster (CODH activity): CO2 + 2H+ + 2e- ↔ CO + H2O

C-cluster (CODH activity): CO2 + 2H+ + 2e- ↔ CO + H2O

B- and D-clusters: electron transfer

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'''α subunit reactions'''

A-cluster (ACS activity): CH3-Co(III)-CFeSP + CO + HSCoA ↔ CH3-CO-SCoA + Co(I)-CFeSP + H+

A-cluster (ACS activity): CH3-Co(III)-CFeSP + CO + HSCoA ↔ CH3-CO-SCoA + Co(I)-CFeSP + H+

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[[Image:C_cluster.JPG|frame|Proposed mechanism for CODH activity in the C-cluster. <ref name="CN"/>]]

In the proposed catalytic action of the C-cluster, CO first binds the Ni ion followed by deprotonation of the Fe-bound water to yield a reactive hydroxide which promotes nucleophilic attack of CO by the hydroxide. Next, the Ni-COOH intermediate is deprotonated to Ni-COO- which allows release of CO2 as the C-cluster is reduced to a new redox state. Then, electrons are shuttled between the B- and D-clusters to reoxidize the C-cluster to its original redox state <ref name="CN"/>. This catalytic cycle is of course operated in reverse to reduce CO2 to CO and allow subsequent production of acetyl-CoA .

In the proposed catalytic action of the C-cluster, CO first binds the Ni ion followed by deprotonation of the Fe-bound water to yield a reactive hydroxide which promotes nucleophilic attack of CO by the hydroxide. Next, the Ni-COOH intermediate is deprotonated to Ni-COO- which allows release of CO2 as the C-cluster is reduced to a new redox state. Then, electrons are shuttled between the B- and D-clusters to reoxidize the C-cluster to its original redox state <ref name="CN"/>. This catalytic cycle is of course operated in reverse to reduce CO2 to CO and allow subsequent production of acetyl-CoA .

Sandbox Reserved 496: Difference between revisions

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@@ Line 41: / Line 41: @@
 '''β subunit reactions'''
-C-cluster (CODH activity): CO2 + 2H<sup>+</sup> + 2e-  ↔  CO + H2O
+C-cluster (CODH activity): CO2 + 2H<sup>+</sup> + 2e<sup>-</sup>  ↔  CO + H2O
 B- and D-clusters: electron transfer
@@ Line 48: / Line 48: @@
 '''α subunit reactions'''
-A-cluster (ACS activity): CH3-Co(III)-CFeSP + CO + HSCoA  ↔  CH3-CO-SCoA +  Co(I)-CFeSP + H+
+A-cluster (ACS activity): CH3-Co(III)-CFeSP + CO + HSCoA  ↔  CH3-CO-SCoA +  Co(I)-CFeSP + H<sup>+</sup>
@@ Line 64: / Line 64: @@
 [[Image:C_cluster.JPG|frame|Proposed mechanism for CODH activity in the C-cluster. <ref name="CN"/>]]
-In the proposed catalytic action of the C-cluster, CO first binds the Ni ion followed by deprotonation of the Fe-bound water to yield a reactive hydroxide which promotes nucleophilic attack of CO by the hydroxide.  Next, the Ni-COOH intermediate is deprotonated to Ni-COO- which allows release of CO2 as the C-cluster is reduced to a new redox state.  Then, electrons are shuttled between the B- and D-clusters to reoxidize the C-cluster to its original redox state <ref name="CN"/>.   This catalytic cycle is of course operated in reverse to reduce CO2 to CO and allow subsequent production of acetyl-CoA .
+In the proposed catalytic action of the C-cluster, CO first binds the Ni ion followed by deprotonation of the Fe-bound water to yield a reactive hydroxide which promotes nucleophilic attack of CO by the hydroxide.  Next, the Ni-COOH intermediate is deprotonated to Ni-COO<sup>-</sup> which allows release of CO2 as the C-cluster is reduced to a new redox state.  Then, electrons are shuttled between the B- and D-clusters to reoxidize the C-cluster to its original redox state <ref name="CN"/>.   This catalytic cycle is of course operated in reverse to reduce CO2 to CO and allow subsequent production of acetyl-CoA .
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