Pecina 2003 Biochim Biophys Acta

Pecina P, Capkova M, Chowdhury SK, Drahota Z, Dubot A, Vojtiskova A, Hansikova H, Houstekova H, Zeman J, Godinot C, Houstek J (2003) Functional alteration of cytochrome c oxidase by SURF1 mutations in Leigh syndrome. Biochim Biophys Acta 1639:53-63.

» PMID: 12943968

Pecina P, Capkova M, Chowdhury SK, Drahota Z, Dubot A, Vojtiskova A, Hansikova H, Houstekova H, Zeman J, Godinot C, Houstek J (2003) Biochim Biophys Acta

Abstract: Subacute necrotising encephalomyopathy (Leigh syndrome) due to cytochrome c oxidase (CIV; COX) deficiency is often caused by mutations in the SURF1 gene, encoding the Surf1 protein essential for CIV assembly. We have investigated five patients with different SURF1 mutations resulting in the absence of Surf1 protein. All of them presented with severe and generalised CIV defect. Immunoelectrophoretic analysis of cultured fibroblasts revealed 85% decrease of the normal-size CIV complexes and significant accumulation of incomplete COX assemblies of 90–120 kDa. Spectrophotometric assay of CIV activity showed a 70–90% decrease in lauryl maltoside (LM)-solubilised fibroblasts. In contrast, oxygen consumption analysis in whole cells revealed only a 13–31% decrease of COX activity, which was completely inhibited by detergent in patient cells but not in controls. In patient fibroblasts ADP-stimulated respiration was 50% decreased and cytofluorometry showed a significant decrease of mitochondrial membrane potential ΔΨm in State 4, as well as a 2.4-fold higher sensitivity of ΔΨm to uncoupler. We conclude that the absence of the Surf1 protein leads to the formation of incomplete CIV complexes, which in situ maintain rather high electron-transport activity, while their H₊-pumping is impaired. Enzyme inactivation by the detergent in patient cells indicates instability of incomplete CIV assemblies. • Keywords: Cytochrome c oxidase, SURF1, Leigh syndrome, Mitochondrial disorder

• O2k-Network Lab: CZ Prague Zeman J, CZ Prague Houstek J, CZ Hradec Kralove Cervinkova Z

Labels: MiParea: Respiration, nDNA;cell genetics, mt-Medicine, Patients  Pathology: Inherited 

Organism: Human  Tissue;cell: Endothelial;epithelial;mesothelial cell, Fibroblast  Preparation: Intact cells, Permeabilized cells  Enzyme: Complex IV;cytochrome c oxidase  Regulation: Coupling efficiency;uncoupling, mt-Membrane potential, Uncoupler  Coupling state: LEAK, OXPHOS, ET  Pathway: S, CIV  HRR: Oxygraph-2k