Department of Life Sciences, National Central University, Taoyuan, Taiwan.
Graduate Institute of Statistics, National Central University, Taoyuan, Taiwan.
Protein Sci. 2024 Jun;33(6):e5028. doi: 10.1002/pro.5028.
Prolyl-tRNA synthetase (ProRS), belonging to the family of aminoacyl-tRNA synthetases responsible for pairing specific amino acids with their respective tRNAs, is categorized into two distinct types: the eukaryote/archaeon-like type (E-type) and the prokaryote-like type (P-type). Notably, these types are specific to their corresponding cognate tRNAs. In an intriguing paradox, Thermus thermophilus ProRS (TtProRS) aligns with the E-type ProRS but selectively charges the P-type tRNA, featuring the bacterium-specific acceptor-stem elements G72 and A73. This investigation reveals TtProRS's notable resilience to the inhibitor halofuginone, a synthetic derivative of febrifugine emulating Pro-A76, resembling the characteristics of the P-type ProRS. Furthermore, akin to the P-type ProRS, TtProRS identifies its cognate tRNA through recognition of the acceptor-stem elements G72/A73, along with the anticodon elements G35/G36. However, in contrast to the P-type ProRS, which relies on a strictly conserved R residue within the bacterium-like motif 2 loop for recognizing G72/A73, TtProRS achieves this through a non-conserved sequence, RTR, within the otherwise non-interacting eukaryote-like motif 2 loop. This investigation sheds light on the adaptive capacity of a typically conserved housekeeping enzyme to accommodate a novel substrate.
脯氨酰-tRNA 合成酶（ProRS）属于氨酰-tRNA 合成酶家族，负责将特定的氨基酸与相应的 tRNA 配对，可分为两种不同的类型：真核生物/古菌样型（E 型）和原核生物样型（P 型）。值得注意的是，这些类型是与其相应的同源 tRNA 特异性相关的。在一个有趣的悖论中，嗜热栖热菌脯氨酰-tRNA 合成酶（TtProRS）与 E 型 ProRS 对齐，但选择性地给 P 型 tRNA 充电，具有细菌特异性的受体茎元件 G72 和 A73。这项研究揭示了 TtProRS 对抑制剂卤夫酮的显著抵抗力，卤夫酮是一种模仿 Pro-A76 的合成衍生物，类似于 P 型 ProRS 的特征。此外，与 P 型 ProRS 类似，TtProRS 通过识别受体茎元件 G72/A73 以及反密码子元件 G35/G36 来识别其同源 tRNA。然而，与依赖于细菌样模体 2 环中严格保守的 R 残基来识别 G72/A73 的 P 型 ProRS 不同，TtProRS 通过非保守序列 RTR 来实现这一点，该序列位于非相互作用的真核样模体 2 环内。这项研究揭示了一种典型保守的管家酶适应新底物的能力。
