Odd-Even Sequence Effect of Surface-Mediated Peptide Assemblies Observed by Scanning Tunneling Microscopy

• Published in: Chinese journal of chemistry 2012-09, Vol.30 (9), p.1987-1991
• Main Author: 郭元元 王晨轩 侯静菲 杨爱华 张雪梅 王宜冰 张敏 杨延莲 王琛
• Format: Article
• Language: English
• Subjects: adsorption; conformation; Microscopy; odd-even effect; peptide; Peptides; scanning tunneling microscopy; 奇偶; 导肽; 序列; 扫描隧道显微镜; 显微镜观察; 组件结构; 组装结构; 表面
• ISSN: 1001-604X; 1614-7065
• DOI: 10.1002/cjoc.201200656

The peptide assembly structures of polyglutamine （PolyQ） have been studied by using scanning tunneling microscopy （STM） with high spatial resolution in ambient conditions. 4,4＇-Bipyridyl （4Bpy） was introduced into the PolyQ7 and PolyQ8 peptide assemblies for labeling the C-termini of the peptides. The fine structures of the 4Bpy-PolyQ7 and 4Bpy-PolyQ8 co-assemblies are observed, and the statistics of the apparent peptide strand length reveal different length distributions for PolyQ7 and PolyQs. One predominant apparent peptide strand length is ob- served for PolyQ7 reflecting one predominant peptide conformation in assembly structures, while three major ap- parent strand lengths can be identified with PolyQ8 reflecting three co-existing peptide conformations in peptide as- semblies. Such drastic difference in assembling characteristics can be considered as a reflection of asymmetric ad- sorption effect ofpeptides relating to odd-even residue numbers of PolyQ7 and PolyQ8,