Mpp7 controls regioselective Knoevenagel condensation during the biosynthesis of Monascus azaphilone pigments

Targeted inactivation of the mpp7 gene in the Monascus azaphilone pigment (MAzP) biosynthetic gene cluster resulted in the accumulation of monasfluol A (7) and B (8), of which the latter was a novel compound, and the abolition of the main MAzPs. It is thus proposed that 7 and 8 are the products of non-enzymatic Knoevenagel condensation followed by a reduction and that Mpp7 assists in regioselective Knoevenagel aldol condensation during MAzP biosynthesis.