Trace Water as Prominent Factor to Induce Peptide Self‐Assembly: Dynamic Evolution and Governing Interactions in Ionic Liquids

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2017-11, Vol.13 (44), p.n/a
• Main Authors: Wang, Juan, Yuan, Chengqian, Han, Yuchun, Wang, Yilin, Liu, Xiaomin, Zhang, Suojiang, Yan, Xuehai
• Format: Article
• Language: English
• Subjects: Biomolecules; Chemical bonds; dipeptide; Evolution; Hydrogen bonds; Hydrophobicity; ionic liquid; Ionic liquids; Ionic Liquids - chemistry; Ions; kinetics and thermodynamics; Moisture content; Nanotechnology; Nanotubes - chemistry; Nanotubes - ultrastructure; Oligomers; Peptides; Peptides - chemistry; Self-assembly; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Synergistic effect; trace water; Water - chemistry
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201702175

The interaction between water and biomolecules including peptides is of critical importance for forming high‐level architectures and triggering life's functions. However, the bulk aqueous environment has limitations in detecting the kinetics and mechanisms of peptide self‐assembly, especially relating to interactions of trace water. With ionic liquids (ILs) as a nonconventional medium, herein, it is discovered that trace amounts of water play a decisive role in triggering self‐assembly of a biologically derived dipeptide. ILs provide a suitable nonaqueous environment, enabling us to mediate water content and follow the dynamic evolution of peptide self‐assembly. The trace water is found to be involved in the assembly process of dipeptide, especially leading to the formation of stable noncovalent dipeptide oligomers in the early stage of nucleation, as evident by both experimental studies and theoretical simulations. The thermodynamics of the growth process is mainly governed by a synergistic effect of hydrophobic interaction and hydrogen bonds. Each step of assembly presents a different trend in thermodynamic energy. The dynamic evolution of assembly process can be efficiently mediated by changing trace water content. The decisive role of trace water in triggering and mediating self‐assembly of biomolecules provides a new perspective in understanding supramolecular chemistry and molecular self‐organization in biology. Trace amounts of water are found to be predominant in triggering peptide selfassembly by using ionic liquids as an environmentally‐benign medium, which enables the dynamic evolution of peptide self‐assembly to be followed.