Site-specific determination of TTR-related functional peptides by using scanning tunneling microscopy  

作　　者：Lanlan Yu Yongfang Zheng JingXu Fuyang Qu Yuchen Lin Yimin Zou Yanlian Yang Sally L. Gras Chen Wang 

机构地区：[1]CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, CAS Center for Excellence in Brain Science, National Center for Nanoscience and Technology, Beijing 100190, China [2]Department of Chemical and Biomolecular Engineering and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia [3]Department of Chemistry, Tsinghua University, Beijing 100084, China [4]University of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Nano Research》2018年第1期577-585,共9页纳米研究（英文版）

摘　　要：For the design and optimization of functional peptides, unravelling the structures of individual building blocks as well as the properties of the ensemble is paramount. TI＇R1, derived from human transthyretin, is a fibril-forming peptide implicated in diseases such as familial amyloid polyneuropathy and senile systemic amyloidosis. The functional peptide TTR1-RGD, based on a TFR1 scaffold, was designed to specifically interact with cells. Here, we used scanning tunneling microscopy （STM） to analyze the assembly structures of TTRl-related peptides with both the reverse sequence and the modified forward sequence. The site- specific analyses show the following： i） The TIR1 peptide is involved in assembly, nearly covering the entire length within the ordered [3-sheet structures, ii） For TTR1-RGD peptide assemblies, the TTR1 motif forms the ordered [3-sheet while the RGDS motif adopts a flexible conformation allowing it to promote cell adhesion. The key site is clearly identified as the linker residue Gly13. iii） Close inspection of the forward and reverse peptide assemblies show that in spite of the difference in chemistry, they display similar assembling characteristics, illustrating the robust nature of these peptides, iv） Glycine linker residues are included in the ^-strands, which strongly suggests that the sequence could be optimized by adding more linker residues. These garnered insights into the assembled structures of these peptides help unravel the mechanism driving peptide assemblies and instruct the rational design and optimization of sequence- programmed peptide architectures.For the design and optimization of functional peptides, unravelling the structures of individual building blocks as well as the properties of the ensemble is paramount. TI＇R1, derived from human transthyretin, is a fibril-forming peptide implicated in diseases such as familial amyloid polyneuropathy and senile systemic amyloidosis. The functional peptide TTR1-RGD, based on a TFR1 scaffold, was designed to specifically interact with cells. Here, we used scanning tunneling microscopy （STM） to analyze the assembly structures of TTRl-related peptides with both the reverse sequence and the modified forward sequence. The site- specific analyses show the following： i） The TIR1 peptide is involved in assembly, nearly covering the entire length within the ordered [3-sheet structures, ii） For TTR1-RGD peptide assemblies, the TTR1 motif forms the ordered [3-sheet while the RGDS motif adopts a flexible conformation allowing it to promote cell adhesion. The key site is clearly identified as the linker residue Gly13. iii） Close inspection of the forward and reverse peptide assemblies show that in spite of the difference in chemistry, they display similar assembling characteristics, illustrating the robust nature of these peptides, iv） Glycine linker residues are included in the ^-strands, which strongly suggests that the sequence could be optimized by adding more linker residues. These garnered insights into the assembled structures of these peptides help unravel the mechanism driving peptide assemblies and instruct the rational design and optimization of sequence- programmed peptide architectures.

关 键 词：TTR1 functional peptide key site scanning tunnelingmicroscopy （STM） optimization 

分 类 号：TP336[自动化与计算机技术—计算机系统结构] TH742[自动化与计算机技术—计算机科学与技术]