Institute of Infection, Immunity and Immunology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
PLoS One. 2012;7(2):e32217. doi: 10.1371/journal.pone.0032217. Epub 2012 Feb 27.
Thiol peroxidase, Tpx, has been shown to be a target protein of the salicylidene acylhydrazide class of antivirulence compounds. In this study we present the crystal structures of Tpx from Y. pseudotuberculosis (ypTpx) in the oxidised and reduced states, together with the structure of the C61S mutant. The structures solved are consistent with previously solved atypical 2-Cys thiol peroxidases, including that for "forced" reduced states using the C61S mutant. In addition, by investigating the solution structure of ypTpx using small angle X-ray scattering (SAXS), we have confirmed that reduced state ypTpx in solution is a homodimer. The solution structure also reveals flexibility around the dimer interface. Notably, the conformational changes observed between the redox states at the catalytic triad and at the dimer interface have implications for substrate and inhibitor binding. The structural data were used to model the binding of two salicylidene acylhydrazide compounds to the oxidised structure of ypTpx. Overall, the study provides insights into the binding of the salicylidene acylhydrazides to ypTpx, aiding our long-term strategy to understand the mode of action of this class of compounds.
硫醇过氧化物酶（Tpx）已被证明是水杨酰腙类抗病毒化合物的靶标蛋白。在这项研究中，我们展示了来自 Yersinia pseudotuberculosis（ypTpx）的 Tpx 的氧化态和还原态的晶体结构，以及 C61S 突变体的结构。所解决的结构与以前解决的非典型 2-Cys 硫醇过氧化物酶一致，包括使用 C61S 突变体的“强制”还原态。此外，通过使用小角 X 射线散射（SAXS）研究 ypTpx 的溶液结构，我们已经证实还原态 ypTpx 在溶液中是同源二聚体。溶液结构还揭示了二聚体界面周围的灵活性。值得注意的是，在催化三联体和二聚体界面的氧化还原状态之间观察到的构象变化对底物和抑制剂的结合有影响。结构数据用于对两种水杨酰腙化合物与 ypTpx 的氧化结构的结合进行建模。总的来说，该研究提供了关于水杨酰腙与 ypTpx 结合的见解，有助于我们长期理解这类化合物的作用模式的策略。
