Fig. 2: Comparison of time-dependent 2D spectra between the rAPC trimer and α-subunit at room temperature.

a Absorptive 2D spectra of the rAPC trimer over time with dashed lines indicating the upper and lower excitonic energy levels. Contour lines are drawn in 7.6% intervals. b Absorptive 2D spectra of the α-subunit with dashed lines indicating the electronic transition energy. Contour lines are drawn in 7.8% intervals. c The energy transfer kinetics of the trimer at the upper diagonal (top) and the cross peak (bottom) respectively. d The energy relaxation kinetics of the trimer at the lower diagonal peak. e The energy relaxation kinetics of the α-subunit at the diagonal peak. The global fits (lines) with a four-exponential function \(f(t)=\mathop{\sum }\nolimits_{i=1}^{4}{A}_{i}\exp (-t/{\tau }_{i})\) are superimposed on the raw data (dots), where τ is lifetime constant, and A is the corresponding coefficient. Only the fastest lifetime constants are shown, and other lifetime constants can be found in Supplementary Fig. 12. The numbers and colors in the legend of (c–e) indicate the positions of the peaks corresponding to these kinetics in the 2D spectra, which are marked with squares in the same color as in a and b. The residues (black lines) show large coherent amplitudes up to 10% on the diagonal peaks relative to the maximum population signal. Source data are provided as a Source Data file.