Peng Zeyu, Peralta Maria D R, Toney Michael D
Department of Chemistry, University of California, Davis , 1 Shields Avenue, Davis, California 95616, United States.
Biochemistry. 2017 Nov 14;56(45):6041-6050. doi: 10.1021/acs.biochem.7b00364. Epub 2017 Nov 3.
The self-assembly of biological molecules into ordered nanostructures is an attractive method for fabricating novel nanomaterials. Nucleic acid-based nanostructures suffer from limitations to functionalization and stability. Alternatively, protein-based nanostructures have advantageous chemical properties, but design facility lags behind that of nucleic acids. Structurally defined fibrils engineered from β-solenoid proteins (BSPs) form under mild conditions [Peralta, M. D. R., et al. (2015) ACS Nano 9, 449-463] and are good candidates for novel nanomaterials because of the defined sequence-to-structure relationship and tunable properties. Here, the stability of two types of engineered fibrils was examined using circular dichroism spectroscopy, transmission electron microscopy, and electrophoresis. Both are stable to at least 90 °C, and one survives autoclaving. They are stable toward organic solvents, urea, and pH extremes. One is even stable in 2% sodium dodecyl sulfate with heating. The fibrils show variable resistance to proteolytic digestion: one is resistant to trypsin, but chymotrypsin and proteinase K degrade both. These results show that BSPs have excellent potential for bottom-up design of rugged, functional, amyloid-based nanomaterials.
生物分子自组装成有序纳米结构是制造新型纳米材料的一种有吸引力的方法。基于核酸的纳米结构在功能化和稳定性方面存在局限性。相比之下，基于蛋白质的纳米结构具有有利的化学性质，但设计便利性落后于核酸。由β-螺旋蛋白（BSPs）工程化构建的结构明确的纤维在温和条件下形成[佩拉尔塔，M. D. R.等人（2015年）《美国化学会纳米》9卷，449 - 463页]，并且由于明确的序列与结构关系以及可调节的性质，是新型纳米材料的良好候选者。在此，使用圆二色光谱、透射电子显微镜和电泳对两种类型的工程化纤维的稳定性进行了研究。两者至少在90℃下稳定，其中一种能经受高压灭菌。它们对有机溶剂、尿素和极端pH稳定。其中一种在加热条件下于2%十二烷基硫酸钠中仍保持稳定。这些纤维对蛋白水解消化表现出不同的抗性：一种对胰蛋白酶有抗性，但胰凝乳蛋白酶和蛋白酶K都会降解两者。这些结果表明，BSPs在自下而上设计坚固、功能性的基于淀粉样蛋白的纳米材料方面具有巨大潜力。
