In vitro studies of maleidride-forming enzymes

In vitro assays of enzymes involved in the biosynthesis of maleidrides from polyketides in fungi were performed. The results show that the enzymes are closely related to primary metabolism enzymes of the citric acid cycle in terms of stereochemical preferences, but with an expanded substrate selectivity. A key citrate synthase can react both saturated and unsaturated acyl CoA substrates to give solely anti substituted citrates. This undergoes anti-dehydration to afford an unsaturated precursor which is cyclised in vitro by ketosteroid-isomerase-like enzymes to give byssochlamic acid.

Automated summary

The study found that the enzymes involved in the biosynthesis of maleidrides from polyketides in fungi are closely related to primary metabolism enzymes of the citric acid cycle, but have expanded substrate selectivity. A key citrate synthase can react with both saturated and unsaturated acyl CoA substrates to produce solely anti-substituted citrates. This anti-dehydration reaction leads to the formation of an unsaturated precursor which is cyclized by ketosteroid-isomerase-like enzymes in vitro to produce byssochlamic acid.