FIGURE 5.

PopB and PopD assemble hexadecameric hetero-complexes in membranes. Protein complexes resulting from the equimolar addition of PopD^BpyTMR (red emitting) and PopB^BpyFL (green emitting) were imaged using dual color single-molecule TIRF microscopy on SLB. A, merge image of single particles containing PopD^BpyTMR (red) and PopB^BpyFL (green). Yellow spots indicate co-localization of PopD^BpyTMR and PopB^BpyFL in individual complexes. B, typical fluorescence intensity time traces for single protein complexes. Photobleaching events appear as stepwise decrease in the intensity. C, quantification of dual-color photobleaching counts obtained from 226 time traces of particles containing both PopD^BpyTMR and PopB^BpyFL. The heat map for observed PopD:PopB distributions is centered at 8 photobleaching counts for PopD and 8 photobleaching counts for PopB.