A new approach for the determination of the amyloid fibril - thioflavin T (ThT) binding parameters (the number of binding modes, stoichiometry, and binding constants of each mode) is proposed. This approach is based on the absorption spectroscopy determination of the concentration of free and bound to fibril dye in solutions, which are prepared by equilibrium microdialysis. Furthermore, the pro...

Aggregation of Ig light chains to form amyloid fibrils is a characteristic feature of light-chain amyloidosis, a light-chain deposition disease. A recombinant variable domain of the light chain SMA was used to form amyloid fibrils in vitro. Fibril formation was monitored by atomic force microscopy imaging. Single filaments 2.4 nm in diameter were predominant at early times; protofibrils 4.0 nm ...

Many insects with smooth adhesive pads can rapidly enlarge their contact area by centripetal pulls on the legs, allowing them to cope with sudden mechanical perturbations such as gusts of wind or raindrops. The short time scale of this reaction excludes any neuromuscular control; it is thus more likely to be caused by mechanical properties of the pad's specialized cuticle. This soft cuticle con...

Interaction between monomer peptides and seeds is essential for clarifying the fibrillation mechanism of amyloid β (Aβ) peptides. We monitored the deposition reaction of Aβ(1-40) peptides on immobilized seeds grown from Aβ(1-42), which caused formation of oligomers in the early stage. The deposition reaction and fibrillation procedure were monitored throughout by novel total-internal-reflection...

Protein misfolding causes serious biological malfunction, resulting in diseases including Alzheimer's disease, Parkinson's disease and cataract. Molecules which inhibit protein misfolding are a promising avenue to explore as therapeutics for the treatment of these diseases. In the present study, thioflavin T fluorescence and transmission electron microscopy experiments demonstrated that hemin p...

Identifying the principles that describe the formation of protein oligomers and fibrils with distinct morphologies is a daunting problem. Here we summarize general principles of oligomer formation gleaned from molecular dynamics simulations of Abeta-peptides. The spectra of high free energy structures sampled by the monomer provide insights into the plausible fibril structures, providing a rati...

We have carried out atomistic molecular dynamics simulations to study the mechanical properties of cellulose nanofibrils in water and ethanol. The studied elementary fibrils consisted of regions having 34 or 36 cellulose chains whose cross-sectional diameter across the fibril was roughly 3.4 nm. The models used in simulations included both crystalline and non-crystalline regions, where the latt...

Alzheimer's disease is a neurodegenerative disorder that is characterized by the cerebral deposition of amyloid fibrils formed by Abeta peptide. Despite their prevalence in Alzheimer's and other neurodegenerative diseases, important details of the structure of amyloid fibrils remain unknown. Here, we present a three-dimensional structure of a mature amyloid fibril formed by Abeta(1-40) peptide,...

The formation of amyloid fibers and their deposition in the body is a characteristic of a number of devastating human diseases. Here, we propose a structural model, based on X-ray diffraction data, for the basic structure of an amyloid fibril formed by using the variants of the B1 domain of IgG binding protein G of Streptococcus. The model for the fibril incorporates four beta sheets in a bundl...

Semicarbazide affected both the final width and stability of fibrils reconstituted from solutions of acid-soluble collagen. Fibril width was increased after semicarbazide treatment at pH2.6 and 4.3, whereas after treatment at pH8.9 it decreased. Fibril stability was decreased after semicarbazide treatment at all values of pH and temperature, indicating the inhibition of intermolecular cross-lin...