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discounted EARLY registration ends Dec 31, 2014
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discounted EARLY registration ends Dec 31, 2014
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MetaCyc Enzyme: Co(II) methylamine-specific corrinoid protein reductase

Gene: ramA Accession Number: G-14856 (MetaCyc)

Species: Methanosarcina barkeri

Summary:
This protein, isolated from Methanosarcina barkeri, catalyzes the reductive activation of the corrinoid proteins that are involved in methylamine:CoM methyl transfer from all three methylamines. For these corrinoid to be active, the cobalt atom must be in the (I) state for activity. However, during catalysis the cobalt is often oxidized to the (II) state, rendering the proteins inactive. This enzyme, which is a monomeric iron-sulfur protein, mediates the ATP-dependent reductive activation of the Co(II) atom to the Co(I) state for all three corrinoid proteins involved in methanogenesis from methylamine, dimethylamine and trimethylamine, namely MtmC, MtbC, and MttC, respectively [Ferguson09].

The ramA gene that encodes the enzyme has been identified and sequenced. The C-terminal contains a ferredoxin-like domain that includes two sequences that might bind tetranuclear iron-sulfur clusters. RamA homologs are widely distributed in genomes near genes encoding corrinoid proteins or their associated methyltransferases [Ferguson09].

The electron donor used in the in vitro assays was Ti(III)-citrate, the in vivo electron donor is not known.

Molecular Weight of Polypeptide: 59.084 kD (from nucleotide sequence), 60.0 kD (experimental) [Ferguson09 ]

Unification Links: Entrez-Nucleotide:FJ477063 , UniProt:B8Y445

Relationship Links: InterPro:IN-FAMILY:IPR001450 , InterPro:IN-FAMILY:IPR017896 , InterPro:IN-FAMILY:IPR017900 , InterPro:IN-FAMILY:IPR026339 , InterPro:IN-FAMILY:IPR027980 , Pfam:IN-FAMILY:PF12838 , Pfam:IN-FAMILY:PF14574 , Prosite:IN-FAMILY:PS00198 , Prosite:IN-FAMILY:PS51379

Gene-Reaction Schematic: ?

Credits:
Created 20-Dec-2011 by Caspi R , SRI International


Enzymatic reaction of: [Co(II) methylamine-specific corrinoid protein] reductase (Co(II) methylamine-specific corrinoid protein reductase)

a [Co(II) methylamine-specific corrinoid protein] + ATP + a reduced electron acceptor <=> a [Co(I) methylamine-specific corrinoid protein] + ADP + an oxidized electron acceptor + phosphate

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

Reversibility of this reaction is unspecified.

Cofactors or Prosthetic Groups: a [4Fe-4S] iron-sulfur cluster [Ferguson09]


Enzymatic reaction of: [Co(II) dimethylamine-specific corrinoid protein] reductase (Co(II) methylamine-specific corrinoid protein reductase)

a [Co(II) dimethylamine-specific corrinoid protein] + ATP + a reduced electron acceptor <=> a [Co(I) dimethylamine-specific corrinoid protein] + ADP + an oxidized electron acceptor + phosphate

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

Reversibility of this reaction is unspecified.

Cofactors or Prosthetic Groups: a [4Fe-4S] iron-sulfur cluster [Ferguson09]


Enzymatic reaction of: [Co(II) trimethylamine-specific corrinoid protein] reductase (Co(II) methylamine-specific corrinoid protein reductase)

a [Co(II) trimethylamine-specific corrinoid protein] + ATP + a reduced electron acceptor <=> a [Co(I) trimethylamine-specific corrinoid protein] + ADP + an oxidized electron acceptor + phosphate

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

Reversibility of this reaction is unspecified.

Cofactors or Prosthetic Groups: a [4Fe-4S] iron-sulfur cluster [Ferguson09]


References

Ferguson09: Ferguson T, Soares JA, Lienard T, Gottschalk G, Krzycki JA (2009). "RamA, a protein required for reductive activation of corrinoid-dependent methylamine methyltransferase reactions in methanogenic archaea." J Biol Chem 284(4);2285-95. PMID: 19043046


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 18.5 on Fri Dec 19, 2014, BIOCYC13B.