Structural analysis of coniferyl alcohol 9-O-methyltransferase from Linum nodiflorum reveals a novel active-site environment.

Coniferyl alcohol 9-O-methyltransferase from Linum nodiflorum (Linaceae) catalyzes the unusual methylation of the side-chain hydroxyl group of coniferyl alcohol. The protein was heterologously expressed in Escherichia coli as a hexahistidine derivative and purified for crystallization. Diffracting crystals were obtained of the pure protein and of its selenomethionine derivative, as well as of complexes with coniferyl alcohol and with S-adenosyl-L-homocysteine together with coniferyl alcohol 9-O-methyl ether (PDB entries 4ems, 4e70 and 4evi, respectively).

Evolution of rosmarinic acid biosynthesis.

Rosmarinic acid and chlorogenic acid are caffeic acid esters widely found in the plant kingdom and presumably accumulated as defense compounds. In a survey, more than 240 plant species have been screened for the presence of rosmarinic and chlorogenic acids. Several rosmarinic acid-containing species have been detected.