Ghosh Goutam, Fernández Gustavo
Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Correnstraße 40, 48149 Münster, Germany.
Beilstein J Org Chem. 2020 Aug 17;16:2017-2025. doi: 10.3762/bjoc.16.168. eCollection 2020.
Peptide-based biopolymers represent highly promising biocompatible materials with multiple applications, such as tailored drug delivery, tissue engineering and regeneration, and as stimuli-responsive materials. Herein, we report the pH- and concentration-dependent self-assembly and conformational transformation of the newly synthesized octapeptide PEP-1. At pH 7.4, PEP-1 forms β-sheet-rich secondary structures into fractal-like morphologies, as verified by circular dichroism (CD), Fourier-transform infrared (FTIR) spectroscopy, thioflavin T (ThT) fluorescence spectroscopy assay, and atomic force microscopy (AFM). Upon changing the pH value (using pH 5.5 and 13.0), PEP-1 forms different types of secondary structures and resulting morphologies due to electrostatic repulsion between charged amino acids. PEP-1 can also form helical or random-coil secondary structures at a relatively low concentration. The obtained pH-sensitive self-assembly behavior of the target octapeptide is expected to contribute to the development of novel drug nanocarrier assemblies.
基于肽的生物聚合物是极具前景的生物相容性材料，具有多种应用，如定制药物递送、组织工程与再生以及作为刺激响应材料。在此，我们报告了新合成的八肽PEP-1的pH和浓度依赖性自组装及构象转变。在pH 7.4时，PEP-1形成富含β-折叠的二级结构，呈分形样形态，这通过圆二色性（CD）、傅里叶变换红外（FTIR）光谱、硫黄素T（ThT）荧光光谱分析和原子力显微镜（AFM）得到验证。改变pH值（使用pH 5.5和13.0）时，由于带电氨基酸之间的静电排斥作用，PEP-1形成不同类型的二级结构及相应形态。在相对较低浓度下，PEP-1也能形成螺旋或无规卷曲二级结构。目标八肽所呈现的pH敏感自组装行为有望推动新型药物纳米载体组装体的发展。
