Characterizing the amino acid activation center of the naturally editing‐deficient aminoacyl‐tRNA synthetase PheRS in Mycoplasma mobile
Characterizing the amino acid activation center of the naturally editing‐deficient aminoacyl‐tRNA synthetase PheRS in Mycoplasma mobile
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DOI：
10.1002/1873-3468.14287
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发表时间：
2022-01
期刊：
影响因子：
3.5
通讯作者：
Nien-Ching Han;A. Kavoor;M. Ibba
中科院分区：
文献类型：
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作者：
Nien-Ching Han;A. Kavoor;M. Ibba
为了确保在蛋白质合成过程中掺入正确的氨基酸，氨酰-tRNA合成酶（aaRS）使用校对机制，统称为编辑。虽然编辑对于生存力很重要，但在宿主依赖性生物体中已鉴定出编辑缺陷型aaRS。在移动的支原体中，已鉴定出编辑缺陷型PheRS和LeuRS。我们表征了MmPheRS的氨基酸激活位点，并鉴定了一个以前未知的超精确突变L287 F。此外，我们报告说，间-Tyr，一种对编辑缺陷细胞有毒的Phe氧化副产物，被MmPheRS激活识别不良，并且不受编辑。此外，表达MmPheRS和超准确变体使大肠杆菌对间-Tyr应激敏感，表明活性位点辨别不足以耐受过量间-Tyr。
To ensure that correct amino acids are incorporated during protein synthesis, aminoacyl‐tRNA synthetases (aaRSs) use proofreading mechanisms collectively referred to as editing. Although editing is important for viability, editing‐deficient aaRSs have been identified in host‐dependent organisms. In Mycoplasma mobile, editing‐deficient PheRS and LeuRS have been identified. We characterized the amino acid activation site of MmPheRS and identified a previously unknown hyperaccurate mutation, L287F. Additionally, we report that m‐Tyr, an oxidation byproduct of Phe which is toxic to editing‐deficient cells, is poorly discriminated by MmPheRS activation and is not subjected to editing. Furthermore, expressing MmPheRS and the hyperaccurate variants renders Escherichia coli susceptible to m‐Tyr stress, indicating that active site discrimination is insufficient in tolerating excess m‐Tyr.