A Single Spherical Assembly of Protein Amyloid Fibrils Formed by Laser Trapping

Abstract

Protein amyloids have received much attention owing to their correlation with serious diseases and to their promising mechanical and optical properties as future materials. Amyloid formation has been conducted by tuning temperature and chemical conditions, so that its nucleation and the following growth are analyzed as ensemble dynamics. A single spherical assembly of amyloid fibrils of cytochrome c domain‐swapped dimer was successfully generated upon laser trapping. The amyloid fibrillar structure was confirmed by fluorescence characterization and electron microscopy. The prepared spheres were further manipulated individually in solution to fabricate a three‐dimensional microstructure and a line pattern. Amyloid formation dynamics and amyloid‐based microstructure fabrication are demonstrated based on direct observation of a single spherical assembly, which foresees a new approach in amyloid studies.

New Aspects of Cytochrome c: 3D Domain Swapping, Membrane Interaction, Peroxidase Activity, and Met80 Sulfoxide Modification

“…65 Additionally, amyloid fibrils of cyt c are obtained by laser trapping the cyt c 3D-DS dimer, whereas it is relatively difficult to obtain amyloid fibrils from the cyt c monomer. 66 These results show that 3D-DS is useful in constructing various oligomers and assemblies of proteins.…”

Use of 3D domain swapping in constructing supramolecular metalloproteins

“…65 The decreased stability of the cyt c 3D-DS dimer compared to the monomer has been utilized to construct amyloid fibrils; amyloid fibrils were obtained by laser trapping the cyt c 3D-DS dimer, whereas it was relatively difficult to obtain amyloid fibrils from the monomer. 66 3D-DS cyt c oligomers dissociate to monomers through exothermic processes. 47 The enthalpy change DH of oligomer dissociation is decreased by B20 kcal mol À1 when the oligomer is elongated by one functional (monomer structure) unit.…”

Oligomerization of cytochrome c, myoglobin, and related heme proteins by 3D domain swapping

“…It has been reported that domain swapping tends to accelerate aggregation of proteins into amyloid-like fibrils [45,66,92,93]. The domain-swapped cyt c dimer formed a spherical assembly of amyloid fibrils by laser trapping, a method in which molecules are concentrated at the focal point, although amyloid fibrils were difficult to form by laser trapping of the cyt c monomer [94]. It was possible to manipulate spherical assemblies individually in solution to fabricate a threedimensional micro-structure and a line pattern.…”