Figure 1
BN–PAGE analysis of membrane proteins with known crystal structures. (a) BN–PAGE and tricine–SDS–PAGE of the 11-subunit bovine heart mitochondrial cytochrome bc1 complex. Two PAGE gels are shown; the left two lanes are results from a BN–PAGE run and are as labeled; the right lane shows the result from tricine–SDS–PAGE (Schagger, 2006) of the same sample, which gives rise to at least ten bands for the intact bovine bc1 complex. Purified bovine bc1 in a buffer (50 mM Tris–HCl pH 8.0 supplemented with 0.66 M sucrose) was diluted to a final concentration of 1 mg ml−1 using the same buffer before a BN–PAGE run. There was no need for additional detergents in the dilution because the purified bovine bc1 contained a sufficient amount of potassium deoxycholate. The arrow indicates the position of the bovine bc1 complex in BN–PAGE. (b) BN–PAGE and tricine–SDS–PAGE of the four-subunit bacterial cytochrome bc1 complex from R. sphaeroides. The Rsbc1 sample in a buffer (50 mM Tris–HCl pH 8.0, 200 mM NaCl, 200 mM histidine, 0.5% β-OG) at a concentration of 1 mg ml−1 was used for BN–PAGE. Two bands were shown by the BN–PAGE as indicated by arrows; the top arrow indicates the position of the three-subunit Rsbc1 complex dimer and the lower arrow indicates the position of the dissociated subunit 4. Four subunits are shown for the same sample by the tricine–SDS–PAGE as indicated. |