Cytochrome C Oxidase Assembly Protein 11 (COX11)

Mutations in the S. cerevisiae cox11 gene result in a 'petite' phenotype, which is associated with a specific defect of COX activity and absence of the absorption bands associated with cytochromes a and a-3. The cox11 protein is a constituent of the inner mitochondrial membrane and, like COX10, may be involved in biosynthesis of heme a, a prosthetic group of the cytochrome oxidase complex.The predicted 276-amino acid human COX11 protein is 41% identical to yeast cox11. COX11 contains a mitochondrial leader peptide and a putative transmembrane domain. Using in vitro mitochondrial import and trypsin-protection assays, the authors demonstrated that the COX11 protein is targeted to mitochondria. Northern blot analysis revealed that COX11 was expressed as 1.7- and 2.7-kb mRNAs in all tissues tested.