title: Tuning self-assembled nanostructures through enzymatic degradation of a peptide amphiphile.
abstract: The enzymatic cleavage of a peptide amphiphile (PA) is investigated. The self-assembly of the cleaved products is distinct from that of the PA substrate. The PA C16-KKFFVLK is cleaved by α-chymotrypsin at two sites leading to products C16-KKF with FVLK and C16-KKFF with VLK. The PA C16-KKFFVLK forms nanotubes and helical ribbons at room temperature. Both PAs C16-KKF and C16-KKFF corresponding to cleavage products instead self-assemble into 5-6 nm diameter spherical micelles, while peptides FVLK and VLK do not adopt well-defined aggregate structures. The secondary structures of the PAs and peptides are examined by FTIR and circular dichroism spectroscopy and X-ray diffraction. Only C16-KKFFVLK shows substantial β-sheet secondary structure, consistent with its self-assembly into extended aggregates, based on PA layers containing hydrogen-bonded peptide headgroups. This PA also exhibits a thermoreversible transition to twisted tapes on heating.
authors: Department of Chemistry, University of Reading, Whiteknights, Reading, United Kingdom.
authors: Ashkan
authors: A
authors: Dehsorkhi
authors: Ian W
authors: IW
authors: Hamley
authors: Jani
authors: J
authors: Seitsonen
authors: Janne
authors: J
authors: Ruokolainen
mesh_terms: D000818:Animals; D002417:Cattle; D002918:Chymotrypsin / Q000737:chemistry; D002942:Circular Dichroism; D006860:Hydrogen Bonding; D008823:Micelles; D043942:Nanotubes / Q000737:chemistry; D010455:Peptides / Q000032:analysis / Q000737:chemistry*; D017433:Protein Structure, Secondary; D059748:Proteolysis; D017550:Spectroscopy, Fourier Transform Infrared; D013501:Surface-Active Agents / Q000032:analysis / Q000737:chemistry*; D013696:Temperature
chemical_list: D008823:Micelles; D010455:Peptides; D013501:Surface-Active Agents; D002918:Chymotrypsin; C117608:alpha-chymotrypsin
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