ARS | Publication request: Self-assembling multidomain peptide fibers with aromatic cores

Submitted to: Biomacromolecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 12, 2013
Publication Date: N/A

Interpretive Summary: This research examines the effect of specific amino acids on protein assemblies. Synthetic peptides containing aromatic amino acids, such as phenylalanine or tryptophan, have been previously shown to have novel self-assembly properties. The contribution of phenylalanine residues in particular is of interest, because phenylalanine residues are prevalent in amyloid beta, a protein linked to the development of Alzheimer’s disease. We found that the introduction of aromatic amino acids has a significant impact on the appearance and behavior of certain nanofibers. Knowing the effect of amino acid selection on peptide structure could help scientists design better biological products, such as cell culture materials and drug delivery systems.

Technical Abstract: Self-assembling multidomain peptides have been shown to have desirable properties, such as the ability to form hydrogels that rapidly recover following shear-thinning and the potential to be tailored by amino acid selection to vary their elasticity and encapsulate and deliver proteins and cells. Here we describe the effects of substitution of aliphatic hydrophobic amino acids in the central domain of the peptide for the aromatic amino acids phenylalanine, tyrosine and tryptophan. While the basic nanofibrous morphology is retained in all cases, selection of the particular core residues results in switching from anti-parallel hydrogen bonding to parallel hydrogen bonding in addition to changes in nanofiber morphology and in hydrogel rheological properties. Peptide nanofiber assemblies are investigated by circular dichroism polarimetry, infrared spectroscopy, atomic force microscopy, transmission and scanning electron microscopy, oscillatory rheology and molecular dynamics simulations. Results from this study will aid in designing next generation cell scaffolding materials.