Exploiting amyloid fibril lamination for nanotube self-assembly.
Fundamental questions about the relative arrangement of the beta-sheet arrays within amyloid fibrils remain central to both its structure and the mechanism of self-assembly. Recent computational analyses suggested that sheet-to-sheet lamination was limited by the length of the strand. On the basis of this hypothesis, a short seven-residue segment of the Alzheimer's disease-related Abeta peptide, Abeta(16-22), was allowed to self-assemble under conditions that maintained the basic amphiphilic character of Abeta. Indeed, the number increased over 20-fold to 130 laminates, giving homogeneous bilayer structures that supercoil into long robust nanotubes. Small-angle neutron scattering and X-ray scattering defined the outer and inner radii of the nanotubes in solution to contain a 44-nm inner cavity with 4-nm-thick walls. Atomic force microscopy and transmission electron microscopy images further confirmed these homogeneous arrays of solvent-filled nanotubes arising from a flat rectangular bilayer, 130 nm wide x 4 nm thick, with each bilayer leaflet composed of laminated beta-sheets. The corresponding backbone H-bonds are along the long axis, and beta-sheet lamination defines the 130-nm bilayer width. This bilayer coils to give the final nanotube. Such robust and persistent self-assembling nanotubes with positively charged surfaces of very different inner and outer curvature now offer a unique, robust, and easily accessible scaffold for nanotechnology.
Lu
Kun
K
Center for the Analysis of Supramolecular Self-assemblies, Departments of Chemistry and Biology, Emory University, Atlanta, Georgia 30322, USA.
Jacob
Jaby
J
Thiyagarajan
Pappannan
P
Conticello
Vincent P
VP
Lynn
David G
DG
D000682:Amyloid / Q000737:chemistry*; D016229:Amyloid beta-Peptides / Q000737:chemistry; D002942:Circular Dichroism; D018625:Microscopy, Atomic Force; D036103:Nanotechnology / Q000379:methods*; D009502:Neutrons; D010446:Peptide Fragments / Q000737:chemistry; D012542:Scattering, Radiation; D014965:X-Rays
D000682:Amyloid; D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; C417223:amyloid beta-protein (16-22)