Diprenylated cyclodipeptide production by changing the prenylation sequence of the nature’s synthetic machinery

Abstract

AbstractAscomycetous fungi are often found in agricultural products and foods as contaminants. They produce hazardous mycotoxins for human and animals. On the other hand, the fungal metabolites including mycotoxins are important drug candidates and the enzymes involved in the biosynthesis of these compounds are valuable biocatalysts for production of designed compounds. One of the enzyme groups are members of the dimethylallyl tryptophan synthase superfamily, which mainly catalyze prenylations of tryptophan and tryptophan-containing cyclodipeptides (CDPs). Decoration of CDPs in the biosynthesis of multiple prenylated metabolites in nature is usually initiated by regiospecificC2-prenylation at the indole ring, followed by second and third ones as well as by other modifications. However, the strict substrate specificity can prohibit the further prenylation of unnaturalC2-prenylated compounds. To overcome this, we firstly obtainedC4-,C5-,C6-, andC7-prenylatedcyclo-l-Trp-l-Pro. These products were then used as substrates for the promiscuousC2-prenyltransferase EchPT1, which normally uses the unprenylated CDPs as substrates. Four unnatural diprenylatedcyclo-l-Trp-l-Pro including the unique unexpectedN1,C6-diprenylated derivative with significant yields were obtained in this way. Our study provides an excellent example for increasing structural diversity by reprogramming the reaction orders of natural biosynthetic pathways. Furthermore, this is the first report that EchPT1 can also catalyzeN1-prenylation at the indole ring.Key points• Prenyltransferases as biocatalysts for unnatural substrates.• Chemoenzymatic synthesis of designed molecules.• A cyclodipeptide prenyltransferase as prenylating enzyme of already prenylated products.Graphical Abstract