Abstract
Pinosylvin O-methyltransferase (PMT) catalyses the transfer of the methyl group of Sadenosyl-L-methionine to the 3-hydroxyl group of the aglycon pinosylvin. Based on RT-PCR using oligonucleotide primers of a highly conserved region of O-methyltransferases (OMT)s a full-length PMT cDNA clone was isolated from an ozone-induced cDNA library. The deduced protein sequence matched that of a tryptic peptide sequence of the purified PMT protein and showed the typical highly conserved regions of OMTs. A search of protein databases revealed highest matches to caffeic acid 3-OMTs (58.5%), caffeoyl-CoA 3-OMTs (21%) pine bifunctional OMTs (39%), flavonoid OMTs (36%) and 3-OH phenol OMTs (51%). PMT expressed in E. coli corresponded to that of purified PMT (40 kDa) from pine cell cultures. The recombinant enzyme catalysed the methylation of pinosylvin, caffeic acid, caffeoyl-CoA and quercetin. Several other substances, e. g. astringenin, resveratrol, 5-OH-ferulic acid, catechol and luteolin were also methylated, while protocatechuic acid, chlorogenic acid, eriodictyol and kaempferol were not transformed. Treatment of 7-year-old Scots pine trees with ozone markedly increased the PMT mRNA level in needles.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call