Figure 5.

Accurate nad1-898 and nad1-937 editing plays an important role in Arabidopsis mitochondrial complex I activity. (A) Comparison of the amino acid identities of NAD1 C-termini from different organisms shows that the conserved edited form of nad1-898 has an amino acid change to Trp and that the less-conserved edited form of nad1-937 has an amino acid change to Ser. The black arrows from the left to right indicate the amino acids translated from the nad1-898 and nad1-937 editing sites, respectively. (B) The significant reduction in mitochondrial complex I activity in the ppme mutant was restored in the complementation lines. Crude total mitochondrial protein extracts from 14-day-old seedlings were separated by native PAGE. The activity was visualized as a purple-blue color resulting from interaction of the substrate (NADH) with the electron acceptor (nitroblue tetrazolium). The left panel shows the total protein profiles, which were determined by silver staining, and the right panel shows the parallel native PAGE staining for assessment of mitochondrial complex I activity. The black arrow shows mitochondrial complex I.