Plant Biotechnology
Online ISSN : 1347-6114
Print ISSN : 1342-4580
ISSN-L : 1342-4580
Original Papers
Mode-of-action and evolution of methylenedioxy bridge forming P450s in plant specialized metabolism
Akio NoguchiManabu HorikawaJun MurataMasayuki TeraYosuke KawaiMasaji IshiguroToshiaki UmezawaMasaharu MizutaniEiichiro Ono
Author information
JOURNAL FREE ACCESS
Supplementary material

2014 Volume 31 Issue 5 Pages 493-503

Details
Abstract

(+)-Sesamin is a major furofran-class lignan in sesame seeds and harbors characteristic two methylenedioxy bridges (MDB) that are sequentially formed from (+)-pinoresinol via (+)-piperitol by a Sesamum indicum P450, CYP81Q1. However, the molecular basis for this unique catalytic activity of CYP81Q1 has been poorly understood. To elucidate MDB formation, we tested various natural and non-natural metabolites as substrates for CYP81Q1. A synthetic (+)-SC1mr and a naturally occurring (+)-kobusin showed inhibitory effect on the production of (+)-sesamin by CYP81Q1 unlike (+)-epipinoresinol and (−)-pinoresinol, indicating the strict diastereomer and enantiomer selectivity. Homology modeling followed by site-directed mutagenesis of CYP81Q1 showed that an amino acid residue crucial for MDB formation is a unique Ala residue (A308), located in I-helix proximal to the substrate pocket, responsible to the conserved distal-Thr residue. MDB by CYP81Q1 is produced possibly through the formation of a substrate-participated hydrogen-bonding network, since single replacement of the Ala by Thr severely and specifically lowered the MDB forming activity. This hypothesis is supported by a newly identified MDB-forming enzyme CYP81Q38 from Phryma leptostachya harboring an Ala responsible to Ala308 in CYP81Q1. An evolutional perspective of CYP81Q1 is discussed in relation to another MDB-forming CYP719As functionally conserved in Ranunculales.

Content from these authors
© 2014 by Japanese Society for Plant Biotechnology
Previous article Next article
feedback
Top