Figure 1.

ATPase activity of the reconstituted ABCD4.A, purified His-ABCD4 (Eluate) and reconstituted His-ABCD4 (liposomes) were subjected to SDS-PAGE, and the gel was stained with Coomassie brilliant blue. The arrow head and asterisk indicate His-ABCD4 and a nonspecific protein, respectively. B, photocrosslinking of His-ABCD4 was performed with succinimidyl 4,4'-azipentanoate (SDA) and UV irradiation. His-ABCD4 was detected by immunoblot analysis with an anti-His antibody. C, ATPase activity of reconstituted ABCD4 was measured. Proteoliposomes containing ABCD4 (6.96 μg) or negative control liposomes containing nonspecific protein (5.39 μg) were incubated with 5 mM ATP at 37 °C, and the phosphate that was released was measured. The ATPase activity of ABCD4 (•) and the negative control (○) are shown. Error bars indicate the standard deviation (n = 3). Differences between the ABCD4 and negative control were considered significant when p < 0.05 or p < 0.01 based on Student's t test (∗p < 0.05; ∗∗p < 0.01). D, different amounts of ABCD4-liposomes or negative control liposomes were incubated with 5 mM ATP at 37 °C for 30 min, and the phosphate that was released was measured. The ATPase activities of ABCD4 (open bar) and a nonspecific protein (gray bar) are shown. Error bars indicate the standard deviation (n = 3). Differences between ABCD4 and the negative control were considered significant when p < 0.05 or p < 0.01 based on Student's t test (∗p < 0.05; ∗∗p < 0.01).