Fig. 3. Transient conformational switching via a non-enzymatic decay route. (a) Schematic representation of transient conformational switching between the unfolding of PN–VN by SDT as the reducing agent and the non-enzymatic re-folding by dissolved oxygen. (b) The appearance of the viologen radical cation (VN˙⁺) assembly band upon reduction with SDT, with the inset showing the corresponding absorption spectra. (c) The absorption changes at λ = 900 nm (characteristic of VN˙⁺ assembly) depicting the transient conformational switching in the presence of SDT and O₂ and the refuelling of the system by subsequent addition of SDT, [SDT] = 5 eq. (d) Dynamic light scattering data depicting the change in size over the transient cycle, [SDT] = 5 eq. (e) Absorption changes at λ = 900 nm depicting the transient conformational switching in the presence of SDT and O₂ and modulation of the lifetime by varying the equivalents of SDT, [SDT] = 3–10 eq. (f) The lifetime of transient conformation by variation of SDT showing a linear increase. The data plotted are the average of four different experiments with their standard deviations. [PN–VN] = 10^–4 M.