Biosynthesis mechanism, genome mining and artificial construction of echinocandin O-sulfonation

Micafungin, a semisynthetic derivative of the cyclic hexapeptide FR901379 produced by Coleophoma empetri fermentation, is the only O-sulfonated echinocandin-type antifungal drug. However, the detailed formation mechanism of O-sulfonate group, whether before or after the assembly of hexapeptide, remains elusive. Here, we confirmed that O-sulfonylation occurs after hexapeptide assembly as a kind of postmodification in the biosynthesis of FR901379. The released cyclic hexapeptide was hydroxylated by cytochrome P450 McfP and successively sulfonated by sulfotransferase McfS. And other three echinocandin sulfotransferases were identified through genome mining by using McfS as a sequence probe. Moreover, pneumocandin B₀, the precursor of caspofungin, could be O-sulfonated by heterologously introducing the McfP-McfS into the pneumocandin B_0-producing species Glarea lozoyensis. The water-solubility of sulfonated pneumocandin B₀ is 4000 times higher than that of pneumocandin B₀. The revealed O-sulfonation mechanism will provide new insights into the design and production of novel sulfonated echinocandins by metabolic engineering.