Title: Target-specific identification and characterization of the putative gene cluster for brasilinolide biosynthesis revealing the mechanistic insights and connic enzymes
Authors: Chiu, Hsien-Tai
Weng, Chien-Pao
Lin, Yu-Chin
Chen, Kuan-Hung
Department of Biological Science and Technology
Issue Date: 2016
Abstract: Brasilinolides exhibiting potent immunosuppressive and antifungal activities with remarkably low toxicity are structurally characterized by an unusual modified 2-deoxy-L-fucose (2dF) attached to a type I polyketide (PK-I) macrolactone. From the pathogenic producer Nocardia terpenica (Nocardia brasiliensis IFM-0406), a 210 kb genomic fragment was identified by target-specific degenerate primers and subsequently sequenced, revealing a giant nbr gene cluster harboring genes (nbrCDEF) required for TDP-2dF biosynthesis and those for PK-I biosynthesis, modification and regulation. The results showed that the genetic and domain arrangements of nbr PK-I synthases agreed colinearly with the PK-I structures of brasilinolides. Subsequent heterologous expression of nbrCDEF in Escherichia coli accomplished in vitro reconstitution of TDP-2dF biosynthesis. The catalytic functions and mechanisms of NbrCDEF enzymes were further characterized by systematic mix-and-match experiments. The enzymes were revealed to display remarkable substrate and partner promiscuity, leading to the establishment of in vitro hybrid deoxysugar biosynthetic pathways throughout an in situ one-pot (iSOP) method. This study represents the first demonstration of TDP-2dF biosynthesis at the enzyme and molecular levels, and provides new hope for expanding the structural diversity of brasilinolides by combinatorial biosynthesis.
URI: http://dx.doi.org/10.1039/c5ob02292d
ISSN: 1477-0520
DOI: 10.1039/c5ob02292d
Volume: 14
Issue: 6
Begin Page: 1988
End Page: 2006
Appears in Collections:Articles