Skip to main content
. 2011 May 13;6(5):e19677. doi: 10.1371/journal.pone.0019677

Figure 5. Reconstituted BmrC/BmrD displays a high and substrate-stimulated ATPase activity.

Figure 5

(a) BmrC/BmrD was reconstituted into proteoliposomes using a mixture of PC/PA (9∶1, molar ratio), and the effect of ATP/Mg2+ concentration on the initial ATPase velocities was determined. The solid line represents the best fit of the data to Michaelis-Menten equation (using the GraFit 5 software from Erithacus), allowing the determination of Vmax = 1.93±0.08 µmol·min−1·mg−1 (kcat∼4.7 sec−1) and K m = 1.0±0.1 mM. Inset shows the Lineweaver-Burk Plot of the data. (b) The ATPase activity of BmrC/BmrD reconstituted in proteoliposomes, prepared either with PC/PA (black) or E. coli lipids (dark gray), was studied in the presence of increasing concentrations of Hoechst 33342. For comparison, the ATPase activity of BmrC/BmrD in 0.05% (w/v) DDM is shown (light gray). The values are expressed as the mean ± SD for three measurements, relative to the ATPase activity obtained without addition of Hoechst 33342.