Extended Data Fig. 7: Density functional theory calculations for tautomerization and redox mechanisms.
From: An NmrA-like enzyme-catalysed redox-mediated Diels–Alder cycloaddition with anti-selectivity
a, The redox-mediated pathway of CtdP catalysis in (S)-[4-2H] NADPH assay. b, Study of the inherent stereoselectivity of the IMDA reaction via the redox-mediated pathway by comparing the four diastereomeric transition states in the absence of the CtdP enzyme. c, DFT computations comparing the redox properties of CtdP substrate 3 and MalC substrate 9. The free energy change for the reaction above (∆G = +4.5 kcal mol–1) corresponds to CtdP substrate 3, with a 6-membered methylpiperidine ring, being over 1000 times harder to oxidize than the corresponding substrate 9-red with a 5-membered pyrrolidine ring.
