Molecular Structure of the Surface-Immobilized Super Uranyl Binding Protein
Molecular Structure of the Surface-Immobilized Super Uranyl Binding Protein
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DOI：
10.1021/acs.jpcb.1c03849
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发表时间：
2021-07-13
影响因子：
3.3
通讯作者：
Chen, Zhan
中科院分区：
文献类型：
--
作者：
Guo, Wen;Zou, Xingquan;Chen, Zhan
近年来，人们研制出一种超铀酰结合蛋白（SUP），该蛋白对铀酰离子的结合具有优异的敏感性和选择性。它可以固定在传感装置的表面上以检测铀酰离子。本研究采用和频产生（sum frequency generation， SFG）振动光谱技术探测表面固定化SUP的界面结构。利用基于SUP晶体结构的单激子哈密顿方法，将收集到的和频产生（sum frequency generation， SFG）振动光谱与计算得到的与取向相关的SUP SFG光谱进行比较，推断出最可能的表面固定化SUP取向。此外，采用离散分子动力学（DMD）模拟技术对表面固定化SUP的构象和取向进行了优化。DMD模拟计算的固定化SUP结构与基于晶体结构分析的SFG数据得到的SUP取向一致，并用于新一轮的SFG取向分析，以更准确地确定铀酰离子结合前后固定化SUP的界面取向和构象。深入了解SUP与表面之间的分子相互作用以及铀酰离子结合对SUP界面结构的影响。我们认为，将SFG测量、DMD模拟和哈密顿数据分析方法相结合的方法可以广泛应用于固体/液体界面生物分子的研究。
Recently, a super uranyl binding protein (SUP) was developed, which exhibits excellent sensitivity/selectivity to bind uranyl ions. It can be immobilized onto a surface in sensing devices to detect uranyl ions. Here, sum frequency generation (SFG) vibrational spectroscopy was applied to probe the interfacial structures of surface-immobilized SUP. The collected SFG spectra were compared to the calculated orientation-dependent SUP SFG spectra using a one-excitonic Hamiltonian approach based on the SUP crystal structures to deduce the most likely surface-immobilized SUP orientation(s). Furthermore, discrete molecular dynamics (DMD) simulation was applied to refine the surface-immobilized SUP conformations and orientations. The immobilized SUP structures calculated from DMD simulations confirmed the SUP orientations obtained from SFG data analyzed based on the crystal structures and were then used for a new round of SFG orientation analysis to more accurately determine the interfacial orientations and conformations of immobilized SUP before and after uranyl ion binding, providing an in-depth understanding of molecular interactions between SUP and the surface and the effect of uranyl ion binding on the SUP interfacial structures. We believe that the developed method of combining SFG measurements, DMD simulation, and Hamiltonian data analysis approach is widely applicable to study biomolecules at solid/liquid interfaces.