Stereospecific elimination of hydrogen atoms with opposite absolute orientations during the biosynthesis of orsellinic acid from chiral malonates in Penicillium cyclopium

Abstract

(R)-[1-¹³C; 2-²H]Malonate and (S)-[1-¹³C; 2-²H]malonate are transformed, using succinyl-CoA transferase, into their paired chiral malonyl-CoA derivatives; incorporation of the malonyl-CoA derivatives into orsellinic acid is acomplished using homogeneous orsellinic acid synthase from Penicillium cyclopium; mass spectrometric analysis of the orsellinic acid reveals that the hydrogen atoms eliminated from the methylene groups at the 2- and 4-positions of the putative polyketide intermediate are from opposite absolute orientations in malonyl-CoA.