Extended Data Fig. 2: The ProTα–H1 dimer is the dominant population in the dilute phase.
Single-molecule transfer efficiency histogram of ProTαC (labeled at position 56 and 110) in the dilute phase at 128 mM ionic strength (TEK buffer including 120 mM KCl). The phase-separated mixture was centrifuged, so that the dense phase coalesced into a single large droplet and no small droplets remained in the dilute phase. The dilute phase was aspirated and transferred into a sample chamber for single-molecule measurements. In the fit (lines), the centers of the Gaussian peak functions were constrained to the transfer efficiencies measured for unbound ProTα and the ProTα–H1 dimer (Fig. 2f) to within experimental uncertainty. The shaded peak near a transfer efficiency of zero originates from molecules lacking an active acceptor dye.
