Mutation in sco affects cytochrome c assembly and alters oxidative stress resistance in Agrobacterium tumefaciens.
Sco (for the synthesis of cytochrome c oxidase) is a mitochondrial membrane protein essential for the correct assembly of cytochrome c oxidase. sco homolog genes exist in a wide variety of bacterial species. Inactivation of Agrobacterium tumefaciens sco leads to markedly decreased cytochrome c oxidase activity. This phenotype can be complemented by either supplementing the culture medium with copper or by a plasmid containing sco. The sco mutant also alters resistance to a superoxide generator menadione and H2O2. Mutational analysis of conserved cysteine residues and a histidine residue within the putative copper ions binding motif of Sco indicates that these residues are essential for the biological activity of Sco. To summarize, we find that A. tumefaciens sco is required for the delivery of copper into active cytochrome c oxidase and in maintaining optimal resistance levels to oxidative stress.
Saenkham
Panatda
P
Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok, Thailand.
Vattanaviboon
Paiboon
P
Mongkolsuk
Skorn
S
D016960:Agrobacterium tumefaciens / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D020816:Amino Acid Motifs; D003300:Copper / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism*; D018869:Heat-Shock Response; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D018384:Oxidative Stress
D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D003300:Copper; D003576:Electron Transport Complex IV