Crystal Structure of a Ten-Amino Acid Protein

What is the smallest protein? This is actually not such a simple question to answer, because there is no established consensus among scientists as to the definition of a protein. We describe here a designed molecule consisting of only 10 amino acids. Despite its small size, its essential characteristics, revealed by its crystal structure, solution structure, thermal stability, free energy surface, and folding pathway network, are consistent with the properties of natural proteins. The existence of this kind of molecule deepens our understanding of proteins and impels us to define an “ideal protein” without inquiring whether the molecule actually occurs in nature.何为最小蛋白质？这实则并非一个简单可答的问题，因为科学界尚未就蛋白质的定义达成公认共识。本文介绍一款仅由10个氨基酸构成的人工设计分子。尽管其体量极小，但通过晶体结构、溶液结构、热稳定性、自由能面以及折叠通路网络所揭示的核心特征，与天然蛋白质的性质高度吻合。这类分子的存在，加深了我们对蛋白质的认知，也促使我们去定义一种"理想蛋白质"，无需考量该分子是否真实存在于自然界中。