Department of Chemistry, Grand Valley State University, Allendale, Michigan, 49401.
Protein Sci. 2018 Apr;27(4):898-902. doi: 10.1002/pro.3384. Epub 2018 Feb 23.
Bacillithiol is a low-molecular weight thiol produced by many gram-positive organisms, including Staphylococcus aureus and Bacillus anthracis. It is the major thiol responsible for maintaining redox homeostasis and cellular detoxification, including inactivation of the antibiotic fosfomycin. The metal-dependent bacillithiol transferase BstA is likely involved in these sorts of detoxification processes, but the exact substrates and enzyme mechanism have not been identified. Here we report the 1.34 Å resolution X-ray crystallographic structure of BstA from S. aureus. Our structure confirms that BstA belongs to the YfiT-like metal-dependent hydrolase superfamily. Like YfiT, our structure contains nickel within its active site, but our functional data suggest that BstA utilizes zinc for activity. Although BstA and YfiT both contain a core four helix bundle and coordinate their metal ions in the same fashion, significant differences between the protein structures are described here.
芽孢硫醇是一种低分子量的巯基化合物，由许多革兰氏阳性菌产生，包括金黄色葡萄球菌和炭疽芽孢杆菌。它是主要的巯基，负责维持氧化还原平衡和细胞解毒，包括抗生素磷霉素的失活。金属依赖性芽孢硫醇转移酶 BstA 可能参与这些解毒过程，但确切的底物和酶机制尚未确定。在这里，我们报告了来自金黄色葡萄球菌的 BstA 的 1.34 Å 分辨率 X 射线晶体结构。我们的结构证实，BstA 属于 YfiT 样金属依赖性水解酶超家族。与 YfiT 一样，我们的结构在其活性位点含有镍，但我们的功能数据表明 BstA 利用锌进行活性。尽管 BstA 和 YfiT 都含有一个核心四螺旋束，并以相同的方式配位其金属离子，但这里描述了蛋白质结构之间的显著差异。
