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Version History for M0126

Annotators:Gemma L. Holliday
Daniel E. Almonacid
Date last updated:06/04/2011

Version 2.0 => Created

Version 2.1 => The acceptor of the electron in the first step, and subsequent donor in the fifth step is assumed to be the closest iron-sulfur cluster (FS4267). The unidentified acid giving a proton in step five is assumed to be the hydroxonium ion. The unidentified bases in step six have been replaced by water molecules.

Version 2.4 => The mechanism for [NiFe] Hydrogenase was incorrect (with thanks to Prof. Richard Cammack for this bug report). Two new references have been added: PMID: 17715982 and PMID: 18633545 which describe the more correct mechanism. There is still some discussion as to which metal ion the hydrogen molecule binds to initially. The residues Glu18B, Cys65B, Cys533B, Cys68B, Ser486B and His72B have been added. Glu18B is thought to be involved in proton shuttling, the other residues are all important in stabilising and activating the metal centre. Whilst we known that Cytochrome c3 is the physiological electron acceptor for this particular hydrogenase, it is a tetraheme cytochrome with all the hemes having different potentials, and probably only one or two are likely to accept electrons from the enzyme under physiological conditions, thus the electron acceptor has been renamed to a generic acceptor, rather than a specific one.

Version 3.0 => A discrepency between the cofactor identifiers in the overall reaction and reaction steps has been corrected.

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