Oxidative phosphorylation in cardiolipin-lacking yeast mitochondria.
The role of cardiolipin in mitochondrial energy transformation was studied by comparing oxidative phosphorylation in the Saccharomyces cerevisiae cardiolipin synthase null mutant crd1Delta, and in isogenic wild type. Oxygen consumption experiments and membrane potential kinetics during the phosphorylation cycle in isolated mitochondria indicated that the absence of cardiolipin causes only a moderate deficiency of mitochondrial energy-transforming machinery at 25 degrees C. However, at 40 degrees C, respiration was completely uncoupled from phosphorylation for the mutant mitochondria, in contrast with that for the wild-type. Membranepotential kinetics demonstrated an increased susceptibility of the mutant mitochondria to gradual deterioration during in vitro incubation. These results suggest that cardiolipin, although normally associated with several of the major enzymes of oxidative phosphorylation and required in vitro for their maximal activity, is not absolutely necessary for mitochondrial energy transformation under optimal conditions. The role of cardiolipin is, rather, to improve efficiency of oxidative phosphorylation and its resistance to unfavourable conditions, such as increased temperature.
Koshkin
V
V
Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA.
Greenberg
M L
ML
D000255:Adenosine Triphosphate / Q000096:biosynthesis / Q000378:metabolism; D000968:Antimycin A / Q000494:pharmacology; D001278:Atractyloside / Q000494:pharmacology; D002244:Carbon / Q000378:metabolism; D002308:Cardiolipins / Q000235:genetics / Q000502:physiology*; D019069:Cell Respiration / Q000187:drug effects; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors / Q000378:metabolism; D005285:Fermentation; D017353:Gene Deletion; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D008565:Membrane Proteins; D008928:Mitochondria / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D010085:Oxidative Phosphorylation; D010100:Oxygen / Q000378:metabolism; D018892:Proton-Motive Force / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013696:Temperature; D017186:Titrimetry; D017855:Transferases (Other Substituted Phosphate Groups) / Q000172:deficiency / Q000235:genetics / Q000378:metabolism
D002308:Cardiolipins; D008565:Membrane Proteins; D001278:Atractyloside; D000968:Antimycin A; D002244:Carbon; D000255:Adenosine Triphosphate; D003576:Electron Transport Complex IV; D017855:Transferases (Other Substituted Phosphate Groups); C100091:cardiolipin synthetase; D010100:Oxygen