Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, India.
Molecular and Structural Biology Department, CSIR - Central Institute of Medicinal and Aromatic Plants, Lucknow, India.
J Pept Sci. 2024 Nov;30(11):e3629. doi: 10.1002/psc.3629. Epub 2024 Jun 19.
The possibility of introducing various functionalities on peptides with relative ease allows them to be used for molecular applications. However, oligopeptides prepared entirely from proteinogenic amino acids seldom assemble as ordered structures on surfaces. Therefore, sidechain modifications of peptides that can increase the intermolecular interactions without altering the constitution of a given peptide become an attractive route to self-assembling them on surfaces. We find that replacing phenylalanine residues with unusual amino acids that have phenylcarbonyl sidechains in oligopeptides increases the formation of ordered self-assembly on a highly ordered pyrolytic graphite surface. Peptides containing the modified amino acids provided extended long-range ordered assemblies, while the analogous peptides containing phenylalanine residues failed to form long-range assemblies. X-ray crystallographic analysis of the bulk structures of these peptides and the analogous peptides containing phenylalanine residues reveal that such modifications do not alter the secondary structure in crystals. It also reveals that the secondary hydrogen bonding interaction through phenylcarbonyl sidechains facilitates extended growth of the peptides on graphite.
通过相对简单的方法在多肽上引入各种功能的可能性，使它们可用于分子应用。然而，完全由蛋白质氨基酸组成的寡肽很少在表面上组装成有序结构。因此，对肽的侧链进行修饰，在不改变给定肽结构的情况下增加分子间相互作用，成为在表面上自组装的一种有吸引力的途径。我们发现，用具有苯甲酰基侧链的非寻常氨基酸替代寡肽中的苯丙氨酸残基，会增加在高度有序的热解石墨表面上形成有序自组装的能力。含有修饰氨基酸的肽提供了扩展的长程有序组装，而含有苯丙氨酸残基的类似肽则无法形成长程组装。这些肽和含有苯丙氨酸残基的类似肽的体相结构的 X 射线晶体学分析表明，这种修饰不会改变晶体中的二级结构。它还表明，通过苯甲酰基侧链的次级氢键相互作用，促进了肽在石墨上的扩展生长。
