Function
Oxidoreductase; part of the gene cluster that mediates the biosynthesis of elsinochromes, pigments consisting of at least four interconvertible tautomers (A, B, C and D) that have a core phenolic quinone to which various side chains are attached and which play an important role in fungal pathogenesis (PubMed:18957608). The non-reducing polyketide synthase PKS1 was proposed to iteratively catalyze decarboxylation between acetyl-CoA and malonyl-CoA subunits for polyketide chain elongation. The released polyketide undergoes cyclization to form an aromatic ring, and proceeds via serial modification steps to produce the heptaketide back- bone of elsinochrome. As elsinochrome has a symmetrical structure, two identical heptaketides are fused to form a core 1,2-dihydrobenzo-perylene ring structure, which can then be successively modified to produce the various derivatives of elsinochrome. Some of these reactions may be cooperatively carried out, at least in part, by the products of RDT1, OXR1 and PKS1. PRF1, embedded within the elsinochrome cluster possibly functions to stabilize some of the biosynthetic enzymes required for elsinochrome production. As prefoldin is a hexamer containing 2 a and 4 b subunits, additional prefoldin subunits, whose coding genes may not immediately link to the elsinochrome biosynthetic gene cluster, are required to fulfill the chaperone function. In addition, no methyltransferase-coding gene exists within the biosynthetic gene cluster, even though elsinochrome has four methyl groups at positions C3, C7, C8 and C12. Apparently, the identified gene cluster does not contain the entire entourage of genes responsible for elsinochrome biosynthesis. Once elsinochrome is synthesized, it must be exported outside the fungal cells, which is probably accomplished by the ECT1 transporter, to avoid toxicity (PubMed:21199563).