Related Experiment Video
Updated: Jun 8, 2026

Sequence-specific Labeling of Nucleic Acids and Proteins with Methyltransferases and Cofactor Analogues
Published on: November 22, 2014
Nickel-alkyl bond formation in the active site of methyl-coenzyme m reductase
Bernhard Jaun1, Rudolf K Thauer
1Organic Chemistry ETHZ, ETH Hönggerberg HCI E317, CH-8093 Zürich, Switzerland jaun@org.chem.ethz.ch.
Abstract:
Methyl-coenzyme M reductase (MCR) catalyzes the methane-forming step in methanogenic archaea and most probably also the methane-oxidizing step in methanotrophic archaea. The enzyme contains coenzyme F(430) as prosthetic group. F(430) is a nickel porphinoid that has to be in the reduced Ni(I) state for the enzyme to be active. The presently discussed catalytic mechanisms of MCR can in principle be divided into two basic models. In one model the key intermediate features a methyl-Ni(III) species being either formed in a nucleophilic substitution reaction or in an oxidative addition reaction. In the other model first the thioether sulfur of methyl-coenzyme M binds to the Ni(I), which subsequently results in the release of the methyl group as methyl radical leaving behind a Ni(II)-sulfur bond. The experimental evidence for and against a methyl-nickel intermediate is reviewed.
Related Concept Videos
Catalysis
Nitriles to Amines: LiAlH4 Reduction
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
Phase II Reactions: Methylation Reactions
The mechanism of methylation unfolds in two stages. The first stage sees a methyltransferase enzyme facilitating the transfer of a methyl group from S-adenosylmethionine (SAM) to the substrate, forming S-adenosylhomocysteine (SAH). The second stage involves further metabolism of SAH into homocysteine, which can be recycled...

