TY - JOUR
T1 - Detailed Mechanistic Study of the Non-enzymatic Formation of the Discoipyrrole Family of Natural Products
AU - Colosimo, Dominic A.
AU - Macmillan, John B.
N1 - Funding Information:
We acknowledge Jonathan R. Goodman and Dr. Wade C. Winkler (University of Maryland) for their gracious contribution in the sequencing and processing of the B. hunanensis SNA-048 genome. We acknowledge following grants for funding of this project: Welch Foundation I-1689, NIH R01CA1499833, NIH U01CA176284, CPRIT RP140152, the Chilton/Bell Foundation, and the Martha Steiner family.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/3/2
Y1 - 2016/3/2
N2 - Discoipyrroles A-D (DPA-DPD) are recently discovered natural products produced by the marine bacterium Bacillus hunanensis that exhibit anticancer properties in vitro. Initial biosynthetic studies demonstrated that DPA is formed in the liquid fermentation medium of B. hunanensis from three secreted metabolites through an unknown but protein-independent mechanism. The increased identification of natural products that depend on non-enzymatic steps creates a significant need to understand how these different reactions can occur. In this work, we utilized 15N-labeled starting materials and continuous high-sensitivity 1H-15N HMBC NMR spectroscopy to resolve scarce reaction intermediates of the non-enzymatic discoipyrrole reaction as they formed in real time. This information guided supplemental experiments using 13C- and 18O-labeled materials to elucidate the details of DPA's non-enzymatic biosynthesis, which features a highly concerted pyrrole formation and necessary O2-mediated oxidation. We have illustrated a novel way of using isotopically enhanced two-dimensional NMR spectroscopy to interrogate reaction mechanisms as they occur. In addition, these findings add to our growing knowledge of how multicomponent non-enzymatic reactions can occur through inherently reactive bacterial metabolites.
AB - Discoipyrroles A-D (DPA-DPD) are recently discovered natural products produced by the marine bacterium Bacillus hunanensis that exhibit anticancer properties in vitro. Initial biosynthetic studies demonstrated that DPA is formed in the liquid fermentation medium of B. hunanensis from three secreted metabolites through an unknown but protein-independent mechanism. The increased identification of natural products that depend on non-enzymatic steps creates a significant need to understand how these different reactions can occur. In this work, we utilized 15N-labeled starting materials and continuous high-sensitivity 1H-15N HMBC NMR spectroscopy to resolve scarce reaction intermediates of the non-enzymatic discoipyrrole reaction as they formed in real time. This information guided supplemental experiments using 13C- and 18O-labeled materials to elucidate the details of DPA's non-enzymatic biosynthesis, which features a highly concerted pyrrole formation and necessary O2-mediated oxidation. We have illustrated a novel way of using isotopically enhanced two-dimensional NMR spectroscopy to interrogate reaction mechanisms as they occur. In addition, these findings add to our growing knowledge of how multicomponent non-enzymatic reactions can occur through inherently reactive bacterial metabolites.
UR - http://www.scopus.com/inward/record.url?scp=84959419230&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84959419230&partnerID=8YFLogxK
U2 - 10.1021/jacs.5b13320
DO - 10.1021/jacs.5b13320
M3 - Article
C2 - 26824832
AN - SCOPUS:84959419230
SN - 0002-7863
VL - 138
SP - 2383
EP - 2388
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 7
ER -