Characterization of YpmQ, an Accessory Protein Required for the Expression of CytochromecOxidase inBacillus subtilis

Neil R. Mattatall, Joanna Jazairi, Bruce C. Hill
2000 Journal of Biological Chemistry  
A search of the Bacillus subtilis genome identifies a potential homolog, ypmQ, of the inner mitochondrial membrane protein Sco1 from yeast. Sco1 has been found to aid the delivery of copper to cytochrome c oxidase. B. subtilis expresses two members of the cytochrome oxidase family, a cytochrome c oxidase that has two copper centers, Cu A and Cu B , and a menaquinol oxidase that has only Cu B . Deletion of ypmQ in B. subtilis depresses expression of cytochrome c oxidase but not menaquinol
more » ... t menaquinol oxidase. Levels of cytochrome c oxidase recover when copper is added to the growth medium of the ⌬ypmQ strain or when ypmQ is expressed from a plasmid. Neither treatment affects the amount or activity of menaquinol oxidase. YpmQ in which two conserved cysteines are replaced by serines and a conserved histidine is replaced by alanine do not complement the deletion of ypmQ even though these mutant forms are found in the membrane extract at a level similar to the wild type protein. We propose that the two cysteines and the histidine are critical for the function of YpmQ and suggest they are involved in copper exchange between YpmQ and the Cu A site of cytochrome c oxidase.
doi:10.1074/jbc.m002741200 pmid:10837475 fatcat:kb3sthpj3bfkjp6hqpfac27fxq