Peptide and protein biomolecules folded into two fundamentally different conformations, either α-helical or β-sheet, carry out dissimilar biological functions. In living organisms, an α-helical secondary structure is adopted by different types of proteins such as myoglobin, keratin, collagen, and more. They can be found in diverse biological tissues of muscle, bone, cartilage, etc.. Biological functions of β-sheet peptide/protein structures are different and associated with a wide range of human mental amyloid diseases such as Alzheimer and Parkinson. The fundamental basis of these diseases is misfolding or refolding of natively soluble α-helical amyloid proteins into solid-state β-sheet fibrillary structures. Bioinspired chemically synthesized biomolecules mimic their biological counterparts. Although these artificial and biological peptides/proteins molecules are completely dissimilar in origin and environment, they demonstrate the common properties of folding and refolding into identical secondary architectures. In this review, we show that these two structural conformations, native (helix-like) and β-sheet, exhibit exclusive and different sets of fold-sensitive physical properties that are surprisingly similar in both biological and bioinspired materials. A native (helix-like) self-assembled fold having asymmetric structure demonstrates ferroelectric-like pyroelectric, piezoelectric, nonlinear optical, and electro-optical effects. β-sheet peptide/protein structures acquire unique visible fluorescence (FL) and reveal a new property of lossless FL photonic transport followed by a long-range FL waveguiding in amyloidogenic fibers. An applied thermally mediated refolding native-to-β-sheet allows us to observe adoption, disappearance, and switching of the revealed physical properties in detail in each fold and study dynamics of all critical stages of refolding from the metastable (native) helix-like conformation via intermediate disordered state to stable β-sheet fibrillary ordering. In the intermediate state, the appearance of the visible FL provides imaging, monitoring, and direct observation of the early stages of seeding and nucleation of β-sheet fibrils. The diverse fold-sensitive physical properties found, give a new insight into biological refolding processes and pave the way for the development of advanced physical methods of fold recognition, bioimaging, light theranostics at nanoscale, and peptide/protein nanophotonics from new visible FL bionanodots to bioinspired multifunctional peptide photonic chips.

中文翻译：

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仿生材料：受生物重折叠控制的物理特性

肽和蛋白质生物分子折叠成两种根本不同的构象，α-螺旋或 β-折叠，执行不同的生物学功能。在生物体中，肌红蛋白、角蛋白、胶原蛋白等不同类型的蛋白质采用 α 螺旋二级结构。它们存在于肌肉、骨骼、软骨等多种生物组织中。β-折叠肽/蛋白质结构的生物学功能各不相同，与阿尔茨海默病和帕金森病等多种人类精神淀粉样疾病有关。这些疾病的基本原理是将天然可溶性 α-螺旋淀粉样蛋白错误折叠或重新折叠成固态 β-折叠纤维结构。Bioinspired 化学合成的生物分子模仿它们的生物对应物。尽管这些人工和生物肽/蛋白质分子在起源和环境上完全不同，但它们展示了折叠和再折叠成相同二级结构的共同特性。在这篇综述中，我们展示了这两种结构构象，天然（螺旋状）和 β-折叠，展示了独特的和不同的折叠敏感物理特性集，这些物理特性在生物和生物启发材料中惊人地相似。具有不对称结构的天然（螺旋状）自组装折叠表现出类铁电热电、压电、非线性光学和电光效应。β-折叠肽/蛋白质结构获得独特的可见荧光 (FL) 并揭示无损 FL 光子传输的新特性，随后在淀粉样纤维中进行远程 FL 波导。应用热介导的再折叠原生到 β-折叠使我们能够在每个折叠中详细观察所揭示的物理特性的采用、消失和转换，并研究亚稳态（原生）螺旋状再折叠的所有关键阶段的动力学构象通过中间无序状态到稳定的 β-折叠纤维排列。在中间状态下，可见 FL 的出现提供了对 β 折叠原纤维播种和成核早期阶段的成像、监测和直接观察。发现的多种折叠敏感物理特性，为生物再折叠过程提供了新的见解，并为折叠识别、生物成像、纳米级光治疗诊断学等先进物理方法的发展铺平了道路，