Article

Biogenesis of mitochondrial inner membrane proteins

Universität Basel, Bâle, Basel-City, Switzerland
Journal of Biological Chemistry (Impact Factor: 4.6). 01/2000; 274(50):35285-8. DOI: 10.1074/jbc.274.50.35285
Source: PubMed
0 Followers
 · 
88 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: The photoreactivity of titania (TiO2) nanoclusters with varying levels of N or Cr-doping, or (Cr, N)-codoping, was systematically investigated using photodegradation of methyl orange in aqueous suspensions. The shifting of the TiO2 absorption edge into the visible spectral region that is primarily attributable to band gap narrowing was found to be a reliable metric for estimating the photoreactivity of the doped nanoclusters. Compared to the weak response with undoped and N-doped TiO2, Cr-doping and (Cr, N)-codoping were found to significantly enhance photodegradation of methyl orange under visible light. The initial reaction rates increase from about 0 to above 1.6×10−2min−1 when the doping concentration of Cr in TiO2 increases from 0 to 5%. In stark contrast, under UV irradiation, doping is not only ineffective but also detrimental to the photoreactivity, and all doping including N or Cr only and (Cr, N)-codoping were found to reduce photoreactivity.
    Applied Catalysis B Environmental 11/2011; 110(10):148-153. DOI:10.1016/j.apcatb.2011.08.037 · 6.01 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The mitochondrial inner membrane of Saccharomyces cerevisiae contains a group of homologous carrier proteins that mediate the exchange of several metabolites. The members of this protein family are synthesized in the cytosol and reach their final topology after translocation across the mitochondrial outer membrane. Using the ADP/ATP carrier (AAC) as a model protein, previous studies have established four distinct steps of the import pathway (stages I-IV). In the absence of the mitochondrial membrane potential (deltapsi), the AAC accumulates at the inner surface of the outer membrane (stage IIIa) and remains bound to the outer membrane import channel. Only in the presence of the membrane potential, can a complex of small Tim proteins mediate transfer of the AAC to the inner membrane. In this study, we characterized the import pathway of the dicarboxylate carrier (DIC). Different from the AAC, the DIC showed complete deltapsi-independent translocation across the outer membrane, release from the import pore, and mainly accumulated in a soluble state in the intermembrane space, thus defining a new translocation intermediate (stage III*). The DIC should be a suitable model protein for the characterization of deltapsi-independent functions of the intermembrane space Tim proteins.
    Journal of Molecular Biology 07/2001; 310(5):965-971. DOI:10.1006/jmbi.2001.4833 · 3.96 Impact Factor