bims-resufa Biomed News
on Respiratory supercomplex factors
Issue of 2021‒02‒21
one paper selected by
Vera Strogolova
Strong Microbials, Inc

  1. Mol Microbiol. 2021 Feb 15.
      Cytochrome c oxidase in the respiratory chain of bacteria and mitochondria couples the reduction of molecular oxygen to form water with the generation of a transmembrane proton gradient. Bacillus subtilis has two heme A-containing heme-copper oxidases-the menaquinol oxidase cytochrome aa3 and the cytochrome c oxidase cytochrome caa3 . By screening three collections of mutants for defective cytochrome c oxidase we found the genes for two new membrane-bound assembly factors in B. subtilis: ytkA and yozB (renamed ctaK and ctaM, respectively). CtaK is a lipoprotein without sequence similarity to any protein of known function. We show that CtaK functions together with Sco1 (YpmQ) in a pathway leading to assembly of the CuA center in cytochrome caa3 and seems to be a functional analogue to proteins of the periplasmic CuA chaperone family (PCuA C). CtaM is required for activity of both cytochrome caa3 and cytochrome aa3 and dispensable for insertion of heme A into these oxidases. The orthologous Bacillus anthracis protein and the distantly related Staphylococcus aureus CtaM complemented CtaM deficiency in B. subtilis establishing a common function of CtaM in these bacteria. As the overall result of our work, 12 different proteins are known to function in biosynthesis of cytochrome c oxidase in B. subtilis.
    Keywords:  CtaK; CtaM; LspA; heme-copper oxidase; metalloenzyme biosynthesis; respiratory chain