The flexible structure of proteins is one important factor in the formation of ordered aggregates (amyloid fibril). This is a major problem for therapeutic proteins such as insulin. Study on the induction and inhibition of insulin fibrillation process with specific compounds such as aromatic derivatives may provide useful information about means of stabilization of protein structures. To induce fibrillation, regular insulin was incubated in phosphate buffer (pH=7.4) during 24 hours. Amyloid formation was investigated by using Congo red absorbance and transmission electron microscopy (TEM). Then nodular amyloidosis was observed in mice upon amyloid fibril injection, after which the excised nodule was studied by Congo red staining and polarized light microscopy. Then, some aromatic compounds effect was investigated on the fibrillation process. Regular insulin form mature amyloid fibrils at pH=7.4, 37°C after 24 hours. Silibinin had the highest inhibitory effect on that process. Furthermore, Amyloid fibril injection in mice caused nodular amyloidosis. Regular insulin has a high potential to undergo amyloid aggregation. Nodular amyloidosis confirms fibril formation by insulin under in vitro condition. Silibinin could be considered as a potential compound capable to increase protein structure stability.

Aim and Amylloid fibrils are filamentus protein aggregates derived from various proteins and peptides. They can be distinguished from other type of features according to their appear shape and electron microscope images, also by dye binding methods, which can indicate induced cross beta structures. Amyloid fibrils are correlated to creating general disease, amyloidosis. Disease such Alzheimer, Parkinson, diabetes type II, and others disease which in each of them, the special kind of protein subjected to form amyloid or amyloid like fibrils. A variety of proteins which they are not converted to amyloid fibrils invivo, can be transform to amyloids in special unstabilizing conditions.
Congored spectrophotometric method, ThT fluorescence and CD Data was used for fibril formation assay and Transmission Electron microscopy was used for final affirmation of fibrils.
results shows that maximum amyloid formation was in 5 mg.ml-1 protein concentration, 50 ºC and 7.4 buffer pH.
With the new approach obtained from the kappa casein, amyloid fibers can be introduced as new nanomaterials, Thus the results, given the diverse applications of nanomaterials, can affirm process optimization of amyloid production from accessible and inexpensive protein in milk.

 Recently, there has been growing efforts to elucidate the molecular mechanism of amyloid formation and investigating effective compounds for inhibiting of amyloid structures. Investigation of the fibrillation process through its induction and inhibition using specific compounds such as aromatic derivatives provide useful information for stabilizing the protein structure. In the present study, the in vitro anti-amyloidogenic and destabilizing effects of Salvia officinalis were investigated using bovine insulin as a model protein.

 To induce fibrillation, the bovine pancreatic insulin was incubated for 10 days in 50 mM glycine buffer at pH = 2.2 at 57° C. Amyloid formation was examined using CR absorption spectroscopy, ANS and THT fluorescence and Field-emission Scanning Electron Microscope (FE-SEM) methods. Then, the effect of different concentrations of Salvia officinalis extract (ratios of 0.1, 1, and 5 extracts to 1 protein) on inhibition of fibrillation and destabilization of pre-formed insulin fibrils was investigated.

 Results indicated a significant decrease in the accumulation of amyloid fibrils in drug-incubated samples compared to control. It also found that Salvia officinalis extract in all concentrations, especially in the 1: 1 ratio of drug to protein, has a strong inhibitory effect on fibrillation and defibrillation of insulin protein.

The results of this study showed that by purification and isolation of effective compounds of Salvia officinalis and its effect on amyloid fibrils, this plant could probably be used to treat amyloid diseases.

Aim and Amyloids are fibrilar protein structures produced from aggregation of proteins and peptide together. In recent years amyloid fibrils are being noticed as new experimental nanomaterials and from this view the induction of proteins to amyloids could be beneficial. In this study, the fibrillation of bovine serum albumin (BSA) as a model protein is optimized.
Different pHs of 1, 2, 3, 4.7 and 7.4 of Bovine Serum Albumin were prepared in Mixed Citrate–Phosphate buffer and agitated for 0, 24, 48 and 72 hour in 100 RPM in various temperatures (40–80 ºC) for preparing protein fibrils. Then the amount of amyloid fibrils was detected by spectrophotometric congored binding assay.
In this research, effect of four variables include temperature, pH, time of incubation and protein concentration was investigated on fibrillogenesis and results were confirmed by congored spectrophotometric method as λmax and absorbance in λmax (Aλmax) accompanying with transmission electron microscopy. The optimum condition for fibrillogenesis was specified in 5 mg.ml-1 of protein and buffer pH of 3 after 72 hour incubation in 70ºC.
Simple congored spectrophotometric method could be used as primary test for evaluating protein nanobiofibrils and absorbance in λmax is introduced as a valid indicator in this way.

Amyloid fibrils are a class of protein nanoparticles in which native proteins are converted into dense fibers. The aggregation can be pathogenic or nonpathogenic. Recently, these fibrils have been considered for the production of Bio– nanomaterials due to their unique structure. In this study, Bovine serum albumin was used as a model protein to optimize the fibrillation process. Concentrations of 2-10 mg/ml were prepared in buffer at different pH values of 3-7 and placed at 0-70 ºC for 0 to 48 hours, and the amounts of produced amyloid fibrils were analyzed by spectrophotometry, fluorimetry and circular dichroism. The spectra obtained from the Congo red absorption method were compared on the basis of the maximum wavelength and absorption at maximum wavelengths with a sample containing Congo red. The concentration of 10 mg/ml of protein, which was 48 hours in buffer at pH = 4 at 50 ºC, produced the highest amounts of amyloid. Optimum conditions were obtained by ThT fluorescence and circular dichroism at a concentration of 10 mg/ml, pH = 4, 70 ºC and 48 hours. The presence of the fibers was confirmed by transmission electron microscope images. The insoluble structure and dimensions of amyloid fibrils can be describe them as new Bio– nanomaterials. Optimizing the production of these structures allows them to be produced at higher scales.

Some of the biological processes, such as mutation, protein misfolding and/or partially unfolding may cause the formation of amyloid fibrils, which have a diameter of nanometer range and a length up to many microns. Extensive studies have demonstrated that the formation of fibrils is associated with a variety of human disorders, such as Alzheimer’s disease, Parkinson’s disease, Huntington’s diseases, type II diabetes, and so on. Therefore, inhibiting fibril formation or disrupting preformed mature fibrils could be beneficial strategies for the treatment of fibril-related diseases. Other investigations have revealed that fibrils feature several fundamental properties, including high structural stability. Thus, they are increasingly exploited for a broad range of applications in Nano biotechnology, such as nanotubes and nanowires. In these cases, materials and compounds that stimulate the in vitro formation of fibrils may contribute to the development of these applications.

In normal physiological conditions, proteins are mostly spherical and water-soluble. In some cases, proteins are converted into structures called fibrils or amyloid plaques that are insoluble and pathogenic. In this study, the effects of hydroalcoholic extracts of Quercus brantii fruit-hull on the formation of hen egg-white lysozyme fibrils as well as the effect of this extract on the elimination of preformed HEWL fibrils have been investigated. For this purpose, lysozyme was incubated in presence and absence of Q. brantii extract at 60 ˚C for 15 days. The effect of extract was evaluated using CR binding assay, CD spectroscopy, THT and ANS fluorescence testing, and FE-SEM microscope.The results showed that Q. brantii extract in all tested ratios has an inhibitory effect on the formation of amyloid fibrils. Also, the extract has an accelerating effect on the defibrillation of amyloid aggregates and the greatest effect of it on defibrillation is observed in the ratio of 0.5: 1 extract to fibril. From the results obtained in this study, it can be concluded that Quercus brantii fruit-hull contains compounds that can be used as agents in the preparation of drugs for the removal of amyloid plaques in the treatment of amyloid-dependent diseases.

Amyloid fibrils are string-like aggregates that form due to the disruption of natural structure and misfolding of various types of peptides and proteins. These amyloid aggregates are associated with some neurodegenerative and systemic diseases such as Alzheimer's, Parkinson's, and type 2 diabetes. The aim of this study was to investigate the inhibitory effects of Trans-chalcone on insulin fibrillation (as a model protein). In this study, insulin was incubated for 24 hours in the presence and absence of Trans-chalcone under amyloid formation conditions. The formed fibrils were analyzed using various techniques including Congo red absorption spectral changes by spectroscopy, electron microscopy images by TEM, and fluorescent staining of amyloid aggregates by fluorescent microscopy. Then, possible interactions between Trans-chalcone and insulin were analyzed using molecular docking method by AutoDock software. The results showed a significant reduction in amyloid fibril formation in the additive-containing sample compared to the control sample. This study provides evidence that Trans-chalcone has an inhibitory effect on insulin fibrillation and could be a potential therapeutic agent for amyloid-related diseases.

Nowadays, study on the abnormal protein aggregation has been interested by researchers in different areas of science especially medicine and biotechnology. The aggregated amyloid fibrils of proteins play the major role in several important diseases including Alzheimer’s’, Parkinson’s’ and type II diabetes. In biotechnology, a major problem during production and purification of the recombinant proteins and peptides is the formation of irreversible aggregates. In the recombinant proteins some tags are usually added in the C-terminal or N-terminal of the genes which can change the physicochemical properties of proteins. So far, no comprehensive study has been carried out on the effect of these sequences on the aggregation of recombinant proteins. In this study, by using AGGRESCAN bioinformatics algorithm, the effect of different tags on propensity of the aggregation of recombinant proteins was investigated. Results demonstrated that the tags can affect the protein aggregation. To determine accuracy of in silico prediction, the fibrillation of alpha-synuclein with or without His-tag was assessed by circular dichroism, atomic force microscopy, fluorimetry and the amyloid standard tests. Alpha-synuclein is the key protein in the development of neurodegenerative diseases by formation the extensive plaques. The bioinformatics program predicted that His-tag can induce the protein tendency to aggregation. Data obtained from experimental study also confirmed the in silico results and showed that the presence of the tag inspire the fibrillation process in alpha-synuclein. Thus it is suggested in many studies, especially studies related to the pathogenesis of fibrillation or exploring the inhibitors of protein aggregation such tags removed from proteins.