Different nanostructures caused by competition of intra- and inter-β-sheet interactions in hierarchical self-assembly of short peptides

Peng Zhou, Li Deng, Yanting Wang, Jian R. Lu, Hai Xu

    Research output: Contribution to journalArticlepeer-review

    Abstract

    To understand how molecular interactions lead to the self-assembly of twisted, helical and flat nanoribbons, we have compared the hierarchical self-assembly processes of three selected octapeptides with the same amino acid composition but different sequences by both experiments and molecular dynamics (MD) simulations. KE-F8 (NH2-KEFFFFKE-CONH2) and EK-F8 (NH2-KEFFFFEK-CONH2) have the same distribution of hydrophobic residues and only differ by swapping the positive and negative charged residues at their C-terminals, while KFE-8 (NH2-KFEFKFEF-CONH2) differs from KE-F8 and EK-F8 by having all hydrophobic and charged residues evenly distributed. MD simulations indicated that the competition between electrostatic and hydrophobic interactions at the molecular level results in different initial packing modes: KE-F8 monomers form completely matched anti-parallel β-sheets, EK-F8 monomers align with one residue shifting, and KFE-8 monomers pack β-sheets with two heterogeneous surfaces, consistent with previously suggested models. Driven by inter-strand and inter-sheet interactions, further growth of these molecular templates leads to larger oligomers with different twisting and stacking degrees, which are structurally consistent with the experimentally observed self-assembled morphologies. Further MD simulations showed that the competition between intra-β-sheet and inter-β-sheet interactions is responsible for the different twisting and stacking degrees of β-sheets and the subsequent formation of different nanostructures (twisted ribbons for KE-F8, helical ribbons/tubes for EK-F8 and flat ribbons for KFE-8). This study thus provided an important mechanistic insight into the fine tuning of molecular packing and interactions via peptide sequence variation leading to controllable self-assembly of twisted, helical and flat nanostructures.

    Original languageEnglish
    Pages (from-to)219-228
    Number of pages10
    JournalJournal of Colloid and Interface Science
    Volume464
    Early online date14 Nov 2015
    DOIs
    Publication statusPublished - 15 Feb 2016

    Keywords

    • Intermolecular interactions
    • Molecular dynamics
    • Molecular packing modes
    • Nanostructures
    • Self-assembly
    • Short peptides

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