Oriented epitaxial growth of amyloid fibrils of the N27C mutant β25–35 peptide

Abstract

Amyloid fibrils are present in the extracellular space of various tissues in neurodegenerative and protein misfolding diseases. Amyloid fibrils may be used in nanotechnology applications, because of their self-assembly properties and stability, if their growth and orientation can be controlled. Recently, we have shown that amyloid beta 25-35 (A beta 25-35) forms a highly oriented, K(+)-dependent network on mica. Here, we analyzed the properties of A beta 25-35_N27C, the cysteine residue of which may be used for subsequent chemical modifications. We find that A beta 25-35_N27C forms epitaxially growing fibrils on mica, which evolve into a trigonally oriented branched network. The binding is apparently more sensitive to cation concentration than that of the wild-type peptide. By nanomanipulating A beta 25-35_N27C fibrils with a gold-coated AFM tip, we show that the sulfhydryl of Cys27 is reactive and accessible from the solution. The oriented network of A beta 25-35_N27C fibrils can therefore be specifically labeled and may be used for constructing nanobiotechnological devices.

Deciphering the Structure, Growth and Assembly of Amyloid-Like Fibrils Using High-Speed Atomic Force Microscopy

“…At this time it is however difficult to elucidate a precise mechanism. It could be due to the fact that, when the angle is smaller than the preferred angle, two fibers have a tendency to laterally associate or to a preferential orientation of fibrils due to interaction with mica as previously described with amyloid proteins such as α-synuclein [46] or Aß peptide [47]. This point remains to be clarified.…”

Structure and assembly–disassembly properties of wild‐type transthyretin amyloid protofibrils observed with atomic force microscopy

“…AFM imaging was carried out by using procedures reported in previous papers on Aß fibrils Kellermayer et al, 2005;Karsai et al, 2006;Karsai et al, 2007;Karsai et al, 2008;Kellermayer et al, 2008) with modifications. Hundred microliters of the diluted WT TTR sample was deposited on freshly cleaved mica, incubated for 5 min at room temperature; the surface was then rinsed with buffer.…”

Kongresse – Symposien – Seminare – Messen

“…An interesting thing is that because of the hexagonal structure of the HOPG lattice, particular orientations of the peptide principal axes and the assembled peptide fiber axes are observed in experiment 28. This phenomenon has also been observed for peptide adsorption on other surfaces 27, 36. We examined the peptide structures from the trajectory files, although it is regretful that we did not observe the specific orientation of the whole peptide chain with respect to the HOPG lattice due to the small timescale that all‐atom simulations could reach, we found that after depositing on the surface, most of the adjacent residues had a tendency to cover the surface in a manner parallel to the three horizontal crystallographic axes of the HOPG surface, also see our previous work for details 29.…”