Figure 4.

Dual quenching of the emission of NBD-labeled PopD in homo-oligomers or hetero-oligomers with PopB. A and B, quenching ratio of NBD-labeled PopD residues in segments H2 (A) and H1 (B) when PopD was reconstituted into hetero-complexes. Quenching ratio was calculated using k_q/(1 − F_doxyl/F₀), where k_q is the bimolecular quenching constant obtained from iodide quenching (a measure of NBD exposure to the aqueous solvent) and the amount of quenching observed when 12-doxyl-PC was incorporated into the liposomes (a measure of NBD exposure to the membrane core). C and D, quenching ratio of NBD-labeled PopD residues in segments H2 (C) and H1 (D) in PopD homo-oligomers. In this case, exposure to the membrane core was calculated using 10-DN and quenching ratio was determined using k_q/(1 − F_10-DN/F₀). Data shown are the mean of two measurements and error bars correspond to the range.