A series of closely related peptide sequences that form triple-strand structures was designed with a variation of cross-strand aromatic interactions and spectroscopically studied as models for β-sheet formation and stabilities. Structures of the three-strand models were determined with NMR methods and temperature-dependent equilibrium studies performed using circular dichroism and Fourier transform infrared spectroscopies. Our equilibrium data show that the presence of a direct cross-strand aromatic contact in an otherwise folded peptide does not automatically result in an increased thermal stability and can even distort the structure. The effect on the conformational dynamics was studied with infrared-detected temperature-jump relaxation methods and revealed a high sensitivity to the presence and the location of the aromatic cross-links. Aromatic contacts in the three-stranded peptides slow down the dynamics in a site-specific manner, and the impact seems to be related to the distance from the turn. With a Xxx-^DPro linkage as a probe with some sensitivity for the turn, small differences were revealed in the relative relaxation of the sheet strands and turn regions. In addition, we analyzed the component hairpins, which showed less uniform dynamics as compared to the parent three-stranded β-sheet peptides.

中文翻译：

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芳族交联在模型三链β-Sheet肽的结构和动力学中的作用

设计了一系列紧密相关的，形成三链结构的肽序列，该结构具有跨链芳族相互作用的变化，并进行了光谱学研究，作为β-折叠形成和稳定性的模型。三链模型的结构通过NMR方法确定，并使用圆二色性和傅立叶变换红外光谱法进行了温度依赖性平衡研究。我们的平衡数据表明，在否则折叠的肽中直接交叉链芳烃接触的存在不会自动导致热稳定性提高，甚至会扭曲结构。用红外检测的温度跳跃松弛方法研究了对构象动力学的影响，并揭示了对芳族交联的存在和位置的高度敏感性。三链肽中的芳香接触以位点特异性方式减慢了动力学，其影响似乎与转弯的距离有关。与Xxx-^D Pro连锁作为对转弯有一定灵敏度的探针，在片股和转弯区域的相对松弛中发现了很小的差异。另外，我们分析了成分发夹，与母体三链β-折叠肽相比，它们显示出更少的均匀动力学。