Structural highlights
Function[7OMT8_MEDSA] Transfers a methyl group to 7-hydroxyls of the isoflavones daidzein, genistein and 6,7,4'-trihydroxyisoflavone. Can also methylate (+)6a-hydroxymaackiain with lower efficiency. Publication Abstract from PubMedChalcone O-methyltransferase (ChOMT) and isoflavone O-methyltransferase (IOMT) are S-adenosyl-l-methionine (SAM) dependent plant natural product methyltransferases involved in secondary metabolism in Medicago sativa (alfalfa). Here we report the crystal structure of ChOMT in complex with the product S-adenosyl-l-homocysteine and the substrate isoliquiritigenin (4,2',4'-trihydroxychalcone) refined to 1.8 A as well as the crystal structure of IOMT in complex with the products S-adenosyl-l-homocysteine and isoformononetin (4'-hydroxy-7-methoxyisoflavone) refined to 1.4 A. These two OMTs constitute the first plant methyltransferases to be structurally characterized and reveal a novel oligomerization domain and the molecular determinants for substrate selection. As such, this work provides a structural basis for understanding the substrate specificity of the diverse family of plant OMTs and facilitates the engineering of novel activities in this extensive class of natural product biosynthetic enzymes. Structures of two natural product methyltransferases reveal the basis for substrate specificity in plant O-methyltransferases.,Zubieta C, He XZ, Dixon RA, Noel JP Nat Struct Biol. 2001 Mar;8(3):271-9. PMID:11224575[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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