Structural basis of transcription inhibition by antibiotic streptolydigin
Structural basis of transcription inhibition by antibiotic streptolydigin
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DOI：
10.1016/j.molcel.2005.07.020
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发表时间：
2005-09-01
期刊：
影响因子：
16
通讯作者：
Vassylyev, DG
中科院分区：
文献类型：
--
作者：
Temiakov, D;Zenkin, N;Vassylyev, DG
链球菌溶血素（Stl）是细菌RNA聚合酶（RNAP）的有效抑制剂。嗜热栖热菌RNAP-Stl复合物的2.4埃分辨率结构表明，与现有的遗传数据完全一致，抑制剂结合位点位于距离RNAP活性位点20埃的位置，并包含桥螺旋和触发环，这两个元素被认为是RNAP催化中心功能的关键。基于结构的生化实验揭示了Stl结合的其他决定因素，并证明Stl不影响NTP底物结合，DNA易位和磷酸二酯键形成。RNAP-Stl复合物的结构，其与密切相关的底物结合的真核转录延伸复合物的比较，和生化分析表明，抑制机制，其中Stl稳定催化失活（插入前）底物结合的转录中间体，从而阻止RNAP的结构异构化到一个积极的配置。该结果为利用Stl样机制设计新的抗生素提供了基础。
Streptolydigin (Stl) is a potent inhibitor of bacterial RNA polymerases (RNAPs). The 2.4 angstrom resolution structure of the Thermus thermophilus RNAP-Stl complex showed that, in full agreement with the available genetic data, the inhibitor binding site is located 20 angstrom away from the RNAP active site and encompasses the bridge helix and the trigger loop, two elements that are considered to be crucial for RNAP catalytic center function. Structure-based biochemical experiments revealed additional determinants of Stl binding and demonstrated that Stl does not affect NTP substrate binding, DNA translocation, and phosphodiester bond formation. The RNAP-Stl complex structure, its comparison with the closely related substrate bound eukaryotic transcription elongation complexes, and biochemical analysis suggest an inhibitory mechanism in which Stl stabilizes catalytically inactive (preinsertion) substrate bound transcription intermediate, thereby blocking structural isomerization of RNAP to an active configuration. The results provide a basis for a design of new antibiotics utilizing the Stl-like mechanism.