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Self-Assembly of Block Heterochiral Peptides into Helical Tapes.

Tara M CloverConor L O'NeillRajagopal AppavuGiriraj LokhandeAkhilesh K GaharwarAmmon E PoseyMark Andrew WhiteJai S Rudra
Published in: Journal of the American Chemical Society (2020)
Patterned substitution of d-amino acids into the primary sequences of self-assembling peptides influences molecular-level packing and supramolecular morphology. We report that block heterochiral analogs of the model amphipathic peptide KFE8 (Ac-FKFEFKFE-NH2), composed of two FKFE repeat motifs with opposite chirality, assemble into helical tapes with dimensions greatly exceeding those of their fibrillar homochiral counterparts. At sufficient concentrations, these tapes form hydrogels with reduced storage moduli but retain the shear-thinning behavior and consistent mechanical recovery of the homochiral analogs. Varying the identity of charged residues (FRFEFRFE and FRFDFRFD) produced similarly sized nonhelical tapes, while a peptide with nonenantiomeric l- and d-blocks (FKFEFRFD) formed helical tapes closely resembling those of the heterochiral KFE8 analogs. A proposed energy-minimized model suggests that a kink at the interface between l- and d-blocks leads to the assembly of flat monolayers with nonidentical surfaces that display alternating stacks of hydrophobic and charged groups.
Keyphrases
  • amino acid
  • molecular docking
  • drug delivery
  • escherichia coli
  • biofilm formation
  • single molecule
  • pseudomonas aeruginosa
  • staphylococcus aureus
  • molecular dynamics simulations
  • energy transfer
  • aqueous solution