Miller J S, Kennedy R J, Kemp D S
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Biochemistry. 2001 Jan 16;40(2):305-9. doi: 10.1021/bi0019500.
Isolating spacers introduced between solubilizing lysine regions and a polyalanine core permit rigorous characterization of context-free alanine helices. The preferred building blocks for isolating spacers are amino acids with rigid, extended conformations such as proline, isonipecotic acid, and tert-leucine. Replacing isolating spacers by conventional N- and C-caps dramatically increases the helicity of dodecaalanine. Solubilized, isolated polyalanines provide optimal tools for testing polypeptide helicity algorithms, central to resolution of the protein folding problem.
在可溶解赖氨酸区域和聚丙氨酸核心之间引入隔离间隔物，能够对无背景丙氨酸螺旋进行严格表征。用于隔离间隔物的优选构建模块是具有刚性、伸展构象的氨基酸，如脯氨酸、异哌啶酸和叔亮氨酸。用常规的N端和C端封端取代隔离间隔物，可显著提高十二聚丙氨酸的螺旋度。溶解的、分离的聚丙氨酸为测试多肽螺旋算法提供了最佳工具，而多肽螺旋算法是解决蛋白质折叠问题的核心。
