Walters Christopher R, Szantai-Kis D Miklos, Zhang Yitao, Reinert Zachary E, Horne W Seth, Chenoweth David M, Petersson E James
Department of Chemistry , University of Pennsylvania , 231 S. 34th Street , Philadelphia , PA 19104 , USA.
Biochemistry and Molecular Biophysics Graduate Group , University of Pennsylvania , 3700 Hamilton Walk , Philadelphia , PA 19104 , USA.
Chem Sci. 2017 Apr 1;8(4):2868-2877. doi: 10.1039/c6sc05580j. Epub 2017 Feb 8.
Thioamides are single atom substitutions of the peptide bond that serve as versatile probes of protein structure. Effective use of thioamides requires a robust understanding of the impact that the substitution has on a protein of interest. However, the thermodynamic effects of thioamide incorporation have only been studied in small structural motifs, and their influence on secondary structure in the context of full-length proteins is not known. Here we describe a comprehensive survey of thioamide substitutions in three benchmark protein systems (calmodulin, the B1 domain of protein G, and collagen) featuring the most prevalent secondary structure motifs: α-helix, β-sheet, and polyproline type II helix. We find that in most cases, effects on thermostability can be understood in terms of the positioning and local environment of the thioamide relative to proximal structural elements and hydrogen bonding networks. These observations set the stage for the rational design of thioamide substituted proteins with predictable stabilities.
硫代酰胺是肽键的单原子取代物，可作为蛋白质结构的通用探针。有效使用硫代酰胺需要深入了解这种取代对目标蛋白质的影响。然而，硫代酰胺掺入的热力学效应仅在小的结构基序中进行过研究，其在全长蛋白质背景下对二级结构的影响尚不清楚。在此，我们描述了对三种基准蛋白质系统（钙调蛋白、蛋白G的B1结构域和胶原蛋白）中硫代酰胺取代的全面研究，这些系统具有最普遍的二级结构基序：α螺旋、β折叠和II型聚脯氨酸螺旋。我们发现，在大多数情况下，对热稳定性的影响可以根据硫代酰胺相对于近端结构元件和氢键网络的位置及局部环境来理解。这些观察结果为合理设计具有可预测稳定性的硫代酰胺取代蛋白质奠定了基础。
