Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
University of Chinese Academy of Sciences, Beijing, China.
Nat Commun. 2022 Jul 20;13(1):4204. doi: 10.1038/s41467-022-31871-7.
Pseudomonas aeruginosa (Pae) SutA adapts bacteria to hypoxia and nutrition-limited environment during chronic infection by increasing transcription activity of an RNA polymerase (RNAP) holoenzyme comprising the stress-responsive σ factor σ (RNAP-σ). SutA shows no homology to previously characterized RNAP-binding proteins. The structure and mode of action of SutA remain unclear. Here we determined cryo-EM structures of Pae RNAP-σ holoenzyme, Pae RNAP-σ holoenzyme complexed with SutA, and Pae RNAP-σ transcription initiation complex comprising SutA. The structures show SutA pinches RNAP-β protrusion and facilitates promoter unwinding by wedging RNAP-β lobe open. Our results demonstrate that SutA clears an energetic barrier to facilitate promoter unwinding of RNAP-σ holoenzyme.
铜绿假单胞菌（Pae）SutA 通过增加由应激反应σ 因子σ（RNAP-σ）组成的 RNA 聚合酶（RNAP）全酶的转录活性，使细菌适应慢性感染期间的缺氧和营养受限环境。SutA 与以前表征的 RNAP 结合蛋白没有同源性。SutA 的结构和作用方式尚不清楚。在这里，我们确定了铜绿假单胞菌 RNAP-σ 全酶、铜绿假单胞菌 RNAP-σ 全酶与 SutA 复合物以及包含 SutA 的铜绿假单胞菌 RNAP-σ 转录起始复合物的冷冻电镜结构。这些结构表明 SutA 挤压 RNAP-β 突出物，并通过将 RNAP-β 叶瓣撑开来促进启动子解旋。我们的结果表明，SutA 清除了能量障碍，从而促进了 RNAP-σ 全酶启动子的解旋。
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