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. 2023 Mar 16;299(5):104614. doi: 10.1016/j.jbc.2023.104614

Figure 5.

Figure 5

Interaction of N-Ret-PL conjugates with ABCA4 and fluorescence emission spectra from prolonged reaction of ATR in PC, PE/PC, or PS/PC liposomes.A, the ATPase activity of ABCA4 in the presence of DOPE, DOPS, or DOPC was measured in the absence (-ATR) and presence (+ATR) of 40 μM ATR used to generate N-Ret-PL conjugates. Data represent the mean ± S.D. for two independent experiments relative to the ATPase activity in the presence of DOPE and the absence of ATR. B, binding of N-Ret-PE or N-Ret-PS to ABCA4. Data displayed as a ratio of counts (dpm) for the binding of N-Ret-PE or N-Ret-PS in the absence of ATP to the binding in the presence of ATP for 3 independent experiments. C, representative fluorescence emission spectra from the reaction of ATR with liposomes composed of PE, PS, and PC. ATR (200 μM) was added to liposomes (228 μM total phospholipid) consisting of 100% DOPC, 35% DOPE/65% DOPC, 35% DOPS/65% DOPC, 12% DOPS/88% DOPC, and incubated at RT for 6 days. The fluorescence emission spectra were recorded 15 min after the addition of ATR on Day 0, and on Day 6. The excitation wavelength was set at 439 nm. Three spectra of each condition were recorded and a representative spectrum from each condition is shown. ATR, all-trans retinal; DOPC, 1,2-dioleoyl-sn-glycero-3-phosphocholine; DOPE, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine; DOPS, 1,2-dioleoyl-sn-glycero-3-phosphoserine; N-Ret-PL, N-retinylidene-phospholipid; PS, phosphatidylserine; PC, phosphatidylcholine; PE, phosphatidylethanolamine.