EC 184.108.40.2066 Enzyme
phpK (gene name);
bcpD (gene name);
Transferring one-carbon groups;
2 S-adenosyl-L-methionine + N-acetyldemethylphosphinothricin + reduced acceptor = S-adenosyl-L-homocysteine + 5'-deoxyadenosine + L-methionine + N-acetylphosphinothricin + oxidized acceptor
reduced acceptor [CPD:
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.
EC 220.127.116.116 created 2016
Phosphonate and phosphinate metabolism
Biosynthesis of secondary metabolites
Kamigiri K, Hidaka T, Imai S, Murakami T, Seto H
Studies on the biosynthesis of bialaphos (SF-1293) 12. C-P bond formation mechanism of bialaphos: discovery of a P-methylation enzyme.
J Antibiot (Tokyo) 45:781-7 (1992)
Hidaka T, Hidaka M, Kuzuyama T, Seto H
Sequence of a P-methyltransferase-encoding gene isolated from a bialaphos-producing Streptomyces hygroscopicus.
Gene 158:149-50 (1995)
Werner WJ, Allen KD, Hu K, Helms GL, Chen BS, Wang SC
In vitro phosphinate methylation by PhpK from Kitasatospora phosalacinea.
Biochemistry 50:8986-8 (2011)
Allen KD, Wang SC
Spectroscopic characterization and mechanistic investigation of P-methyl transfer by a radical SAM enzyme from the marine bacterium Shewanella denitrificans OS217.
Biochim Biophys Acta 1844:2135-44 (2014)
Hu K, Werner WJ, Allen KD, Wang SC
Investigation of enzymatic C-P bond formation using multiple quantum HCP nuclear magnetic resonance spectroscopy.
Magn Reson Chem 53:267-72 (2015)
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