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Your query returned 1 entry. Printable version
EC | 2.1.1.326 | ||||||||||
Accepted name: | N-acetyldemethylphosphinothricin P-methyltransferase | ||||||||||
Reaction: | 2 S-adenosyl-L-methionine + N-acetyldemethylphosphinothricin + reduced acceptor = S-adenosyl-L-homocysteine + 5′-deoxyadenosine + L-methionine + N-acetylphosphinothricin + oxidized acceptor (overall reaction) (1a) S-adenosyl-L-methionine + cob(I)alamin = S-adenosyl-L-homocysteine + methylcob(III)alamin (1b) methylcob(III)alamin + N-acetyldemethylphosphinothricin + S-adenosyl-L-methionine = cob(III)alamin + N-acetylphosphinothricin + 5′-deoxyadenosine + L-methionine (1c) cob(III)alamin + reduced acceptor = cob(I)alamin + oxidized acceptor |
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Glossary: | N-acetyldemethylphosphinothricin = (2S)-2-acetamido-4-phosphinatobutanoate | ||||||||||
Other name(s): | phpK (gene name); bcpD (gene name); P-methylase | ||||||||||
Systematic name: | S-adenosyl-L-methionine:N-acetyldemethylphosphinothricin P-methyltransferase | ||||||||||
Comments: | The enzyme was originally characterized from bacteria that produce the tripeptides bialaphos and phosalacine, which inhibit plant and bacterial glutamine synthetases. It is a radical S-adenosyl-L-methionine (SAM) enzyme that contains a [4Fe-4S] center and a methylcob(III)alamin cofactor. According to the proposed mechanism, the reduced iron-sulfur center donates an electron to SAM, resulting in homolytic cleavage of the carbon-sulfur bond to form a 5′-deoxyadenosyl radical that abstracts the hydrogen atom from the P-H bond of the substrate, forming a phosphinate-centered radical. This radical reacts with methylcob(III)alamin to produce the methylated product and cob(II)alamin, which is reduced by an unknown donor to cob(I)alamin. A potential route for restoring the latter back to methylcob(III)alamin is a nucleophilic attack on a second SAM molecule. The enzyme acts in vivo on N-acetyldemethylphosphinothricin-L-alanyl-L-alanine or N-acetyl-demethylphosphinothricin-L-alanyl-L-leucine, the intermediates in the biosynthesis of bialaphos and phosalacine, respectively. This transformation produces the only example of a carbon-phosphorus-carbon linkage known to occur in nature. | ||||||||||
Links to other databases: | BRENDA, EXPASY, KEGG, MetaCyc | ||||||||||
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