Figure 2. Self-quenching of Rho labelled at the N-terminus of FP to probe self-assembly of FP in the membrane bilayer under pH cycle (pH 4.8→7.3→4.7).

(a), Labelled/unlabelled FP 1:19 (w/w); (b), labelled FP only. The relative intensity is shown in the inset. The former represents inter-trimer association, whereas the latter reflects intra-trimer association. Both sets of results show that FP has higher propensity for self-assembly at acidic pH in a pH-reversible manner.