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Chemical activation; Macrophages; Medical applications; Peptides; Solutions; X ray diffraction; X ray scattering, Biomedical applications; Critical aggregation concentration; Lipopeptides; Molecular packings; Raft structure; Self-assemble; Toll-like receptors; Twisted tapes, Self assembly, macrophage activating lipopeptide 2; lipopeptide; macrophage stimulatory lipopeptide 2; peptide fragment, aqueous solution; Article; beta sheet; chemical structure; morphology; priority journal; protein aggregation; protein assembly; protein motif; protein secondary structure; X ray crystallography; X ray diffraction; amino acid sequence; chemistry; molecular genetics; protein multimerization; small angle scattering, Amino Acid Sequence; Lipopeptides; Molecular Sequence Data; Peptide Fragments; Protein Multimerization; Scattering, Small Angle; X-Ray Diffraction
Abstract:
The self-assembly of the macrophage-activating lipopeptide MALP-2 in aqueous solution has been investigated and is compared to that of the constituent peptide GNNDESNISFKEK. MALP-2 is a toll-like receptor agonist lipopeptide with diverse potential biomedical applications and its self-assembly has not previously been examined. It is found to self-assemble, above a critical aggregation concentration (cac), into remarkable "fibre raft" structures, based on lateral aggregation of β-sheet based bilayer tapes. Peptide GNNDESNISFKEK also forms β-sheet structures above a cac, although the morphology is distinct, comprising highly extended and twisted tape structures. A detailed insight into the molecular packing within the MALP-2 raft and GNNDESNISFKEK nanotape structures is obtained through X-ray diffraction and small-angle X-ray scattering. These results point to the significant influence of the attached lipid chains on the self-assembly motif, which lead to the raft structure for the lipopeptide assemblies. © 2016 American Chemical Society.
