---

Aim and Background: 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.
Materials and Methods: 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: results shows that maximum amyloid formation was in 5 mg.ml-1 protein concentration, 50 ºC and 7.4 buffer pH.

Conclusion:
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.

---

Protein deposition due to the process of accumulation inside or outside cells causes many neurological diseases such as Alzheimerchr('39')s, Huntingtonchr('39')s or Parkinsonchr('39')s seizures. Parkinsonchr('39')s disease is the second most common neurological disease after Alzheimerchr('39')s, in which patients develop disorders due to the accumulation of leprosy and the destruction of dopamine neurons. Alpha-synuclein protein contains 140 amino acids, the main protein known in lewy body accumulations. During the aggregation process, alpha-synuclein protein monomers bind together as oligomers and eventually become amyloid filaments. So far, there is no drug to stop or delay the progression of Parkinsonchr('39')s, but studies on the molecular mechanism of amyloid formation and the identification of inhibitors are increasing. For this purpose, in this study, the effect of BRICHOS domain resulting from BRI2, which can have various functions, including antimicrobial properties, on the process of alpha-synuclein accumulation as a model protein was investigated.The gene was first optimized and synthesized and then multiplied by PCR. The product was digested by enzymes Xho I and Nde1 and entered the expression vector pET28 a, which was transformed into E. coli bacteria.Finally, the peptide was purified by nickel chromatography. The alpha-synuclein gene was also expressed separately and purified.The anti-cumulative effect of BRICHOS domain on alpha-synuclein fibrillation was investigated using Toflavin T fluorescence method and TEM technique.

---

Transthyretin (TTR)  is a highly conserved 55 kDa homotetrameric protein that exists in several vertebrate species including humans, bacteria, nematodes, and plants. Previous studies have shown a direct interaction between TTR and amyloid beta (Aβ) (the causative agent of Alzheimer's disease), which leads to the inhibition of Aβ aggregation, fibrillar destruction, or both. In recent years, evidence has shown that the oligomeric species of Aβ formed by the aggregation process are more toxic than mature fibrils. Studies have shown that such an oligomeric mediator is modulated by interaction with TTR. However, the exact mechanism of binding of Aβ to TTR has not yet been determined. In this study, after the purification of human transthyretin protein, the inhibitory effects of TTR on the formation of Aβ were shown in different ways, and finally, the role of hydrophobicity interactions in the chaperone activity of TTR was investigated with the help of protein surface hydrophobicity (PSH) measurement studies. The Scatchard diagram for quantitative measurement of PSH indicates an increase in the hydrophobicity of TTR after binding to oligomeric forms of Aβ. The results presented in this research provide insight into the nature and interactions involved in the initial stages of fibril formation in Aβ and its interaction with TTR. The results showed that hydrophobic interactions probably play a role in the binding between TTR and Aβ. Considering the similarity of amyloid formation systems, the described findings of this study can provide a deeper understanding of the pathology of amyloid diseases.

---

Alzheimer’s disease (AD) is the most common type of dementia in the elderly. The neuropathology and treatment of AD is not precisely determined yet, but according to the pathological studies, AD is associated with presence of toxic soluble oligomers and insoluble senile plaques formed by amyloidosis of Amyloid Beta (Aβ) in neocortical region of brain. The V10HHQKLVFFAE22 is a critical region of Aβ42 which facilitates aggregation process. An attractive therapeutic approach to treat AD is to identify small ligands that are capable of binding to critical residues in order to inhibit or reverse Aβ amyloidosis process as source of neurotoxicity. In this area, therapeutic efforts designed various organic agents and most of them focused on the N-terminal sequence of Aβ. Here, a peptide inhibitor derived from the C-terminal of Aβ (G33LMVG37) is utilized as inhibitor and combined Docking and Molecular dynamics simulation used to find the binding sights in the critical region (V10HHQKLVFFAE22). The simulation identified tree stable binding sites for Aβ42 inhibition by penta peptide. This result indicate that this penta-peptide is capable to inhibit aggregation process and can be consider as an drug for AD preclinical studies.

---

Alpha-synuclein protein (α-syn) is the main factor known in Parkinson's disease. The expression of this protein has challenges. One of these challenges is the presence of protein in bacterial pellet. Studies have shown that the expression of proteins with tags such as small ubiquitin-like modifier (SUMO) increases the expression in the soluble phase, therefore the expression of α-syn with this sequence was investigated to increase the protein in the soluble phase. It has also been shown in studies that SUMOylation has an inhibitory effect on fibrillation, also in this study the effect of the SUMO on alpha-synuclein fibrillation was investigated. The α-syn gene was cloned with SUMO-tag. Nickel sepharose column was used to purify the protein, and dialysis was performed and fibrillation was checked by fluorescence emission of Thioflavin for 72 hours and was observed that the protein with SUMO sequence has a higher expression level, and 95% of the protein is in the soluble phase. On the other hand, it was shown that the SUMO sequence has an inhibitory effect on the process of amyloid fibril formation. The results obtained from previous studies showed that the binding of the SUMO sequence increases the expression and solubility of recombinant proteins. This study revealed that the presence of this sequence contributed to the protein expression level and the protein's presence in the solution phase. On the other hand, observations showed that this sequence has anti-fibrillation properties for proteins with amyloid properties, and in this study showed that SUMO prevents α-syn aggregation.
 

---

Introduction: Amyloid beta (Aβ) is the major constituent of harmful plaques in the Alzheimer’s patients. Thus, study of Aβ and understanding its related molecular and cellular mechanisms is essential for diagnosis and therapeutic interventions. This study introduces a rapid, simple, and cost-effective technique for production and purification of this peptide, utilizing the expression of Aβ gene within bacterial system.
Materials and methods: Aβ gene was synthesized and transferred into the expression vector pET26b. After induction by Lactose and  24 hours of incubation for Aβ expression the cell sediment was analyzed for presence of recombinant peptide using SDS-PAGE and Western blot.  Then the purification of recombinant peptide was carried using nickel chloride affinity chromatography. Characterization of purified Aβ was performed by evaluating cell cytotoxicity in 25 µM and 50 µM concentrations using MTT assay on Alzheimer cell line model SH-SY5Y.
Results: Colony PCR and sequencing results showed the correct insertion of Aβ coding fragment into the expression vector. Presence of bands with the expected size in the results of SDS PAGE and western blot had confirmed successful expression of his-tagged recombinant peptide. MTT assay results showed the purified peptide has respectively 30 and 50% cytotoxicity for 25 µM and 50 µM concentrations.
Discussion: Production of amyloid beta peptide in bacterial hosts seems to be favorable. Obtaining Aβ peptide in soluble phase is an important advantage of this study. Hence according to toxicity of the purified peptide, it can be utilized for cell line treatments and further researches on Alzheimer disease.
 

---

Alzheimer is the most common form of dementia. Amyloid beta peptides play a key role in the pathology of Alzheimer and the recent surveys have demonstrated that amyloid beta oligomers are the most toxic component of them. Among oligomers, considering the high durability of dimer in comparison to other kinds, it has more toxic effects. Prefoldin is a molecular chaperone which prevents accumulation of misfolded proteins. Prefoldin is demonstrated that it can also operate as a nano actuator. In this article, we investigate the interaction between the prefoldin nano actuator and dimeric pathogenic nano cargo in molecular dimensions, hence the all-atom molecular dynamic simulation in explicit solvent were performed at physiological temperature. Visualizing the results and investigating the atomic distance between nano actuator and pathogenic nano cargo revealed that two arms of six arms of prefoldin nano actuator have been able to capture cargo and during the simulation they have made hydrogen bonds. Furthermore, investigating the hydrophobic effects between the hydrophobic amino acids in the cargo and nano actuator revealed that these effects have positively affected the stability of the binding between arms and the cargo. This article introduces the prefoldin as an inhibitor factor for dimeric oligomer from amyloid beta.

---

Objective: Alzheimer's disease (AD) is the most common form of dementia in the elderly. One of the major pathological hallmarks of AD is extracellular deposition of aggregated beta-amyloid (Aβ) peptide in the brain. Aβ causes neural cell death through several mechanisms. New treatments for AD focus on compounds that can modify disease progression and reduce symptoms through several mechanisms. Medicinal plants include several compounds with heterogeneous pharmacological effects that can be effective in the treatment of AD through different mechanisms. The aim of this study is to evaluate the protective effect of a methanolic extract of seven medicinal plants from Iran on Aβ induced toxicity in a cell culture model. Methods: We cultured PC12 cells according to standard protocols. The cells were incubated with Aβ alone or with different concentrations of extracts for 24 hours. Cell viability was measured using the MTT assay. Results: Sanguisorba minor, Cerasus microcarpa, Ferulago angulate,andRosa caninasignificantly reduced Aβ-induced cell death in the PC12 cell culture. The observed protective effects of extracts were dose-dependent. We did not observe any protective effects with the Stachys pilifera,Amygdalus scoparia, and Alhagi pseudalhagi extracts. Conclusion: Sanguisorba minor, Cerasus microcarpa,Ferulago angulate, andRosa canina extracts could be considered for treatment of AD.

---