Presilphiperfolan-8-beta-ol synthase

UniProtKB accession:  Q6WP50

Grouped By:  Matching UniProtKB accession

UniProtKB description:  Presilphiperfolan-8-beta-ol synthase; part of the gene cluster that mediates the biosynthesis of botrydial (PubMed:14651630, PubMed:19035644, PubMed:19476353). Botrydial is necessary for colonization of plant tissue by the T4 strain (PubMed:19035644). It is a strain-dependent virulence factor since highly aggressive strains like SAS56 or B05 still retain substantial virulence when botrydial synthesis is impaired, since they produce also botcinic acid (PubMed:15986930). The first step of botrydial biosynthesis is performed by the sesquiterpene synthase BOT2 which catalyzes the cyclization of farnesyl diphosphate (FPP) to presilphiperfolan-8-beta-ol (PSP) (PubMed:19035644, PubMed:19476353). The cytochrome P450 monooxygenase BOT4 then catalyzes the hydroxylation at C-4 to give a probotryane intermediate (PubMed:27529428, PubMed:28617493). Acetylation of the hydroxyl at C-4 is carried out by the acetyltransferase BOT5, followed by the combined action of the P450 monooxygenases BOT3 and BOT1, to yield finally the glycol, via the regio- and stereospecific hydroxylations at C-10 and C-15 of the probotryane intermediates, respectively (PubMed:15986930, PubMed:27529428). The cleavage of the C10-C15 bond of probotryane skeleton is an intriguing and chemically important reaction, which could be mediated by some of the monooxygenases or by a combination of them (PubMed:27529428). It is possible that either BOT3 or BOT1 would oxidize either the 10- or the 15-hydroxy group to the hydroperoxide derivative, which would then undergo heterolytic fragmentation to give the dialdehyde botrydial (PubMed:27529428). Finally, the dehydrogenase BOT7 might be involved in the conversion of botrydial to dihydrobotrydial (PubMed:27721016).