Saenkham Panatda, Vattanaviboon Paiboon, Mongkolsuk Skorn
Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok, Thailand.
FEMS Microbiol Lett. 2009 Apr;293(1):122-9. doi: 10.1111/j.1574-6968.2009.01516.x. Epub 2009 Feb 7.
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.
Sco（细胞色素c氧化酶合成相关蛋白）是一种线粒体膜蛋白，对于细胞色素c氧化酶的正确组装至关重要。sco同源基因存在于多种细菌物种中。根癌土壤杆菌sco的失活会导致细胞色素c氧化酶活性显著降低。通过向培养基中补充铜或含有sco的质粒，可以弥补这种表型。sco突变体还会改变对超氧化物生成剂甲萘醌和过氧化氢的抗性。对Sco假定的铜离子结合基序内保守的半胱氨酸残基和组氨酸残基进行突变分析表明，这些残基对于Sco的生物学活性至关重要。总之，我们发现根癌土壤杆菌sco对于将铜传递到活性细胞色素c氧化酶中以及维持对氧化应激的最佳抗性水平是必需的。
