Immunoblots of membrane preparations from four stop codon substitutions in nuoK. Six independent blots were performed with each mutant, using antibodies against subunits K, L, M, N, A, and F. The antibodies used are indicated at the right of the blots. The arrows indicate the position of the band detected by the listed antibody. For comparison, the null strain, BA14, and the wild type strain, BA14/pBA400, were included in each blot. Each lane contained 40 μg of protein.