Unexpected enzyme-catalysed [4+2] cycloaddition and rearrangement in polyether antibiotic biosynthesis

Author(s):Show less -

Little, Rory ^[1] ; Paiva, Fernanda C. R. ^[2] ; Jenkins, Robert ^[3] ; Hong, Hui ^[1] ; Sun, Yuhui ^[4] ; Demydchuk, Yuliya ^{[1, 5]} ; Samborskyy, Markiyan ^[1] ; Tosin, Manuela ^[3] ; Leeper, Finian J. ^[6] ; Dias, Marcio V. B. ^{[2, 3]} ; Leadlay, Peter F. ^[1]

Affiliation

^[1] Univ Cambridge, Dept Biochem, Cambridge - England

^[2] Univ Sao Paulo, Inst Biomed Sci 2, Dept Microbiol, Sao Paulo, SP - Brazil

^[3] Univ Warwick, Dept Chem, Coventry, W Midlands - England

^[4] Wuhan Univ, Sch Pharmaceut Sci, Key Lab Combinatorial Biosynth & Drug Discovery, Minist Educ, Wuhan, Hubei - Peoples R China

^[5] Bicycle Therapeut Ltd, Babraham Res Campus, Cambridge - England

^[6] Univ Cambridge, Dept Chem, Cambridge - England

• Document type: Journal article
• Source: NATURE CATALYSIS; v. 2, n. 11, p. 1045-1054, NOV 2019.
• Web of Science Citations: 0

Abstract

Enzymes that catalyse remarkable Diels-Alder-like {[}4+2] cyclizations have been previously implicated in the biosynthesis of spirotetronate and spirotetramate antibiotics. Biosynthesis of the polyether antibiotic tetronasin is not expected to require such steps, yet the tetronasin gene cluster encodes enzymes Tsn11 and Tsn15, which are homologous to authentic {[}4+2] cyclases. Here, we show that deletion of Tsn11 led to accumulation of a late-stage intermediate, in which the two central rings of tetronasin and four of its twelve asymmetric centres remain unformed. In vitro reconstitution showed that Tsn11 catalyses an apparent inverse-electron-demand hetero-Diels-Alder-like {[}4+2] cyclization of this species to form an unexpected oxadecalin compound that is then rearranged by Tsn15 to form tetronasin. To gain structural and mechanistic insight into the activity of Tsn15, the crystal structure of a Tsn15-substrate complex has been solved at 1.7 angstrom resolution. (AU)

• FAPESP's process: 15/09188-8 - Biosynthesis of polyether and aminoglycoside antibiotics: structural investigation of unusual enzymes or with synthetic biology applicability
• Grantee: Marcio Vinicius Bertacine Dias
• Support Opportunities: Regular Research Grants
• FAPESP's process: 17/50140-4 - Mechanisms of ring formation in inophore polyether tetronates
• Grantee: Marcio Vinicius Bertacine Dias
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/00351-1 - Applied structural biology involved in the biosynthesis of natural products: biotechnolgical aplications and study of unusual molecular reactions
• Grantee: Marcio Vinicius Bertacine Dias
• Support Opportunities: Regular Research Grants