Structural insights into the redox-switch mechanism of the MarR/DUF24-type regulator HypR.
Structural insights into the redox-switch mechanism of the MarR/DUF24-type regulator HypR.
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DOI：
10.1093/nar/gkr1316
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发表时间：
2012-05
影响因子：
14.9
通讯作者：
Antelmann H
中科院分区：
文献类型：
--
作者：
Palm GJ;Khanh Chi B;Waack P;Gronau K;Becher D;Albrecht D;Hinrichs W;Read RJ;Antelmann H
枯草芽孢杆菌编码OhrR和DUF 24家族的氧化还原感测MarR型调节剂，其通过基于硫醇的氧化还原开关感测有机氢过氧化物、二酰胺、醌或醛。在这篇文章中，我们表征了新的氧化还原传感马尔/DUF 24家族调节器HypR（YybR），该调节器在B中由二酰胺和NaOCl引起的二硫胁迫下被激活。枯草芽孢杆菌HypR积极控制黄素氧化还原酶HypO，赋予保护免受NaOCl胁迫。HypR的保守N-末端Cys 14残基具有较低的pKa 6.36，并且对于通过二硫胁迫激活hypO转录是必需的。HypR类似于一个2-Cys型调节因子，通过Cys 14-Cys 49 ′亚基间二硫键形成激活。还原和氧化的HypR蛋白质的晶体结构被解析，揭示了氧化后HypR的结构变化。在还原HypR中，氢键网络稳定了与Cys 49 ′相距8-9个碱基的反应性Cys 14硫醇盐。HypR氧化会破坏这些氢键，使单体重新定向，并使主要沟识别α4和α4′螺旋相互移动。这是细菌中氧化还原敏感马尔/DUF 24家族蛋白的第一个晶体结构，该蛋白被NaOCl胁迫激活。由于次氯酸是由活化的巨噬细胞释放的，因此相关的HypR样调节剂可以起保护病原体免受宿主免疫防御的作用。
Bacillus subtilis encodes redox-sensing MarR-type regulators of the OhrR and DUF24-families that sense organic hydroperoxides, diamide, quinones or aldehydes via thiol-based redox-switches. In this article, we characterize the novel redox-sensing MarR/DUF24-family regulator HypR (YybR) that is activated by disulphide stress caused by diamide and NaOCl in B. subtilis. HypR controls positively a flavin oxidoreductase HypO that confers protection against NaOCl stress. The conserved N-terminal Cys14 residue of HypR has a lower pKa of 6.36 and is essential for activation of hypO transcription by disulphide stress. HypR resembles a 2-Cys-type regulator that is activated by Cys14–Cys49′ intersubunit disulphide formation. The crystal structures of reduced and oxidized HypR proteins were resolved revealing structural changes of HypR upon oxidation. In reduced HypR a hydrogen-bonding network stabilizes the reactive Cys14 thiolate that is 8–9 Å apart from Cys49′. HypR oxidation breaks these H-bonds, reorients the monomers and moves the major groove recognition α4 and α4′ helices ∼4 Å towards each other. This is the first crystal structure of a redox-sensing MarR/DUF24 family protein in bacteria that is activated by NaOCl stress. Since hypochloric acid is released by activated macrophages, related HypR-like regulators could function to protect pathogens against the host immune defense.