Fig 9.

The 13.4L protein stabilizes complex I assembly intermediates. (A and B) Conversion of complex I from nuo13.4 into intermediate a upon oxidative stress induction. The nuo13.4 mutant was grown at 26°C in the presence or absence of 10 mM H₂O₂ for the last 3 h of growth. Mitochondria were then analyzed by BN PAGE (A) followed by two-dimensional BN SDS-PAGE (B). The 1D gel was probed with AS-13.4L, and the 2D gels were analyzed with antisera as indicated on the left. (C) Schematic representation of the final steps of complex I assembly. Late assembly intermediates of complex I present in the different mutant strains and mature complex I (gray), incomplete subdomains (white), and 13.4L assembly factor (black). The mutant strains indicated represent those in which such intermediates accumulate. N, Q, and P are distinct functional domains of the mature enzyme.