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Chemical and Genetic Studies on the Formation of Pyrrolones During the Biosynthesis of Cytochalasans
Author(s) -
Zhang Haili,
Hantke Verena,
Bruhnke Pia,
Skellam Elizabeth J.,
Cox Russell J.
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202004444
Subject(s) - knoevenagel condensation , tautomer , biosynthesis , complementation , chemistry , stereochemistry , enzyme , aldehyde , biochemistry , gene , catalysis , mutant
A key step during the biosynthesis of cytochalasans is a proposed Knoevenagel condensation to form the pyrrolone core, enabling the subsequent 4+2 cycloaddition reaction that results in the characteristic octahydroisoindolone motif of all cytochalasans. In this work, we investigate the role of the highly conserved α,β‐hydrolase enzymes PyiE and ORFZ during the biosynthesis of pyrichalasin H and the ACE1 metabolite, respectively, using gene knockout and complementation techniques. Using synthetic aldehyde models we demonstrate that the Knoevenagel condensation proceeds spontaneously but results in the 1,3‐dihydro‐2 H ‐pyrrol‐2‐one tautomer, rather than the required 1,5‐dihydro‐2 H ‐pyrrol‐2‐one tautomer. Taken together our results suggest that the α,β‐hydrolase enzymes are essential for first ring cyclisation, but the precise nature of the intermediates remains to be determined.