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fibril structure

Ning-Hui Lu, Su-Chun How, Chien-Yu Lin, Shen-Long Tsai, Zuzana Bednarikova, Diana Fedunova, Zuzana Gazova, Josephine W Wu, Steven S-S Wang
More than thirty human proteins and/or peptides can aggregate to form amyloid deposits that are linked to several amyloid diseases including clinical syndrome injection-localized amyloidosis, which is correlated with the aggregation of the 51-residue polypeptide insulin. While no cure is currently available toward tackling amyloid diseases, prevention or suppression of amyloid fibrillization is considered as the primary therapeutic strategy. Nanomaterials have been demonstrated to possess great potential in the fields of biomedical diagnosis and drug delivery, they are also able to affect the amyloid aggregation of proteins...
September 14, 2018: Colloids and Surfaces. B, Biointerfaces
Lei Wang, Chuansheng Cui, Rui Li, Shuling Xu, Haibo Li, Lianzhi Li, Jifeng Liu
Oxidative stress accompanies various diseases associated with chronic inflammation. In this work, H2 O2 and H2 O2 -Fe3 O4 magnetic nanoparticles were used as two reactive oxygen species to study the oxidative stress for the structure and polymerization behaviour of fibrinogen molecules. The alterations of secondary structure and component of fibrinogen molecule were characterized by circular dichroism spectra, ultraviolet-visible spectra and fluorescence spectra, the viscoelasticity of fibrinogen solution was studied by dynamic light scattering microrheology...
September 12, 2018: Journal of Inorganic Biochemistry
Haruki Koike, Ryoji Nishi, Shohei Ikeda, Yuichi Kawagashira, Masahiro Iijima, Takeo Sakurai, Takayoshi Shimohata, Masahisa Katsuno, Gen Sobue
INTRODUCTION: We evaluated the morphology of amyloid fibrils in the peripheral nervous system using biopsy or autopsy specimens from hereditary transthyretin amyloidosis patients. The impact of amyloid fibril formation on neighboring tissues was also investigated. METHODS: Sural nerve biopsy specimens from 34 patients were examined using electron microscopy. Twenty-eight patients had Val30Met mutations, and the remaining 6 patients had non-Val30Met mutations (i...
September 12, 2018: Journal of the Neurological Sciences
Mohammad Khursheed Siddiqi, Parvez Alam, Sadia Malik, Nabeela Majid, Sumit Kumar Chaturvedi, Sudeepa Rajan, Mohd Rehan Ajmal, Mohsin Vahid Khan, Vladimir N Uversky, Rizwan Hasan Khan
Amyloid fibrillation is associated with several human maladies, such as Alzheimer's, Parkinson's, Huntington's diseases, prions, amyotrophic lateral sclerosis, and type 2 diabetes diseases. Gaining insights into the mechanism of amyloid fibril formation and exploring novel approaches to fibrillation inhibition are crucial for preventing amyloid diseases. Here, we hypothesized that ligands capable of stabilizing the native state of query proteins might prevent protein unfolding, which, in turn, may reduce the propensity of proteins to form amyloid fibrils...
September 22, 2018: Journal of Cellular Biochemistry
Hilary A Weismiller, Rachel Murphy, Guanghong Wei, Buyong Ma, Ruth Nussinov, Martin Margittai
The intracellular deposition of fibrils composed of the microtubule-associated protein Tau is a characteristic feature of Alzheimer's disease (AD) and other fatal neurodegenerative disorders collectively known as tauopathies. Short Tau fibrils spread intracerebrally through transfer between interconnected neurons. Once taken up by a recipient cell, Tau fibrils recruit Tau monomers onto their ends. Based on the number of microtubule-binding repeats, there are two distinct groups of Tau isoforms: three-repeat (3R) Tau and four-repeat (4R) Tau...
September 21, 2018: Journal of Biological Chemistry
Julia Liu, Debashish Das, Fan Yang, Andrea G Schwartz, Guy M Genin, Stavros Thomopoulos, Ioannis Chasiotis
As the fundamental structural protein in mammals, collagen transmits cyclic forces that are necessary for the mechanical function of tissues, such as bone and tendon. Although the tissue-level mechanical behavior of collagenous tissues is well understood, the response of collagen at the nanometer length scales to cyclical loading remains elusive. To address this major gap, we cyclically stretched individual reconstituted collagen fibrils, with average diameter of 141±53 nm, to small and large strains in the partially hydrated conditions of 60% RH...
September 18, 2018: Acta Biomaterialia
Daniel de Melo Pereira, Pamela Habibovic
Synthetic substitutes of bone grafts, such as calcium phosphate-based ceramics, have shown some good clinical successes in the regeneration of large bone defects and are currently extensively used. In the past decade, the field of biomineralization has delivered important new fundamental knowledge and techniques to better understand this fascinating phenomenon. This knowledge is also applied in the field of biomaterials, with the aim of bringing the composition and structure, and hence the performance, of synthetic bone graft substitutes even closer to those of the extracellular matrix of bone...
September 21, 2018: Advanced Healthcare Materials
Matthew G Iadanza, Matthew P Jackson, Eric W Hewitt, Neil A Ranson, Sheena E Radford
The aggregation of proteins into amyloid fibrils and their deposition into plaques and intracellular inclusions is the hallmark of amyloid disease. The accumulation and deposition of amyloid fibrils, collectively known as amyloidosis, is associated with many pathological conditions that can be associated with ageing, such as Alzheimer disease, Parkinson disease, type II diabetes and dialysis-related amyloidosis. However, elucidation of the atomic structure of amyloid fibrils formed from their intact protein precursors and how fibril formation relates to disease has remained elusive...
September 20, 2018: Nature Reviews. Molecular Cell Biology
David F Holmes, Ching-Yan Chloé Yeung, Richa Garva, Egor Zindy, Susan H Taylor, Yinhui Lu, Simon Watson, Nicholas S Kalson, Karl E Kadler
The formation of uniaxial fibrous tissues with defined viscoelastic properties implies the existence of an orchestrated mechanical interaction between the cytoskeleton and the extracellular matrix. This study addresses the nature of this interaction. The hypothesis is that this mechanical interplay underpins the mechanical development of the tissue. In embryonic tendon tissue, an early event in the development of a mechanically robust tissue is the interaction of the pointed tips of extracellular collagen fibrils with the fibroblast plasma membrane to form stable interface structures (fibripositors)...
September 20, 2018: Proceedings of the National Academy of Sciences of the United States of America
Sandra M Correa-Garhwal, R Crystal Chaw, Thomas H Clarke, Liliana G Alaniz, Fanny S Chan, Rachael E Alfaro, Cheryl Y Hayashi
Most spiders spin multiple types of silk, including silks for reproduction, prey capture, and draglines. Spiders are a megadiverse group and the majority of spider silks remain uncharacterized. For example, nothing is known about the silk molecules of Tengella perfuga, a spider that spins sheet webs lined with cribellar silk. Cribellar silk is a type of adhesive capture thread composed of numerous fibrils that originate from a specialized plate-like spinning organ called the cribellum. The predominant components of spider silks are spidroins, members of a protein family synthesized in silk glands...
2018: PloS One
Maria Chiara di Gregorio, Leana Travaglini, Alessandra Del Giudice, Jacopo Cautela, Nicolae Viorel Pavel, Luciano Galantini
Bile salts (BSs) are naturally occurring rigid surfactants with a steroidal skeleton and specific self-assembly and interface behaviors. Using bile salts as precursors, derivatives can be synthesized to obtain molecules with specific functionalities and amphiphilic structure. Modifications on single molecules are normally performed by substituting the least hindered hydroxyl group on carbon C-3 of the steroidal A ring or at the end of the lateral chain. This leads to mono-steroidal rigid building blocks often able to self-organize into 1D structures such as tubules, twisted ribbons or fibrils with a helical supramolecular packing...
September 20, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Márcia Vagos, Ilsbeth G M van Herck, Joakim Sundnes, Hermenegild J Arevalo, Andrew G Edwards, Jussi T Koivumäki
The pathophysiology of atrial fibrillation (AF) is broad, with components related to the unique and diverse cellular electrophysiology of atrial myocytes, structural complexity, and heterogeneity of atrial tissue, and pronounced disease-associated remodeling of both cells and tissue. A major challenge for rational design of AF therapy, particularly pharmacotherapy, is integrating these multiscale characteristics to identify approaches that are both efficacious and independent of ventricular contraindications...
2018: Frontiers in Physiology
Jichao Zhao, Ulrich Schotten, Bruce Smaill, Sander Verheule
Background: Atrial fibrillation (AF) leads to a loss of transverse connections between myocyte strands that is associated with an increased complexity and stability of AF. We have explored the interaction between longitudinal and transverse coupling, and the relative contribution of the sodium (INa ) and calcium (ICa ) current to propagation, both in healthy tissue and under diseased conditions using computer simulations. Methods: Two parallel strands of atrial myocytes were modeled (Courtemanche et al. ionic model)...
2018: Frontiers in Physiology
Neil Mangrolia, Prakash Punjabi
Atrial fibrillation is associated with a significantly increased risk of stroke, and oral anticoagulation is the mainstay of preventative treatment. Scenarios arise where the risks of treatment with oral anticoagulation may outweigh the benefits, most commonly when there is an elevated risk of bleeding. Studies of percutaneous closure of the left atrial appendage have strongly implicated this structure in the etiology of stroke in atrial fibrillation, and provide some rationale for the discontinuation of oral anticoagulation following percutaneous closure device implantation...
September 20, 2018: Future Cardiology
Valeria Castelletto, Ian W Hamley, Jani Seitsonen, Janne Ruokolainen, Gemma Harris, Kathrin Bellmann-Sickert, Annette G Beck-Sickinger
The gastric peptide hormone human PYY3-36 is a target for the development of therapeutics, especially for treatment of obesity. The conformation and aggregation behaviour of PEGylated and lipidated derivatives of this peptide is examined using a combination of fluorescence dye assays, circular dichroism (CD) spectroscopy, analytical ultracentrifugation (AUC) measurements, small-angle x-ray scattering (SAXS) and cryogenic-transmission electron microscopy (cryo-TEM). The behaviour of two PYY3-36 derivatives lipidated (with octyl chains) in different positions is compared to that of two derivatives with PEG attached at different residues and to that of the native peptide...
September 19, 2018: Biomacromolecules
I V Kudryakova, A G Gabdulkhakov, S V Tishchenko, V Ya Lysanskaya, N E Suzina, I M Tsfasman, A S Afoshin, N V Vasilyeva
The Gram-negative bacterium Lysobacter sp. XL1 secretes into the extracellular space five bacteriolytic enzymes that lyse the cell walls of competing microorganisms. Of special interest are homologous lytic proteases L1 and L5. This work found protein L5 to possess Gly-Gly endopeptidase and N-acetylmuramoyl-L-Ala amidase activities with respect to staphylococcal peptidoglycan. Protein L5 was found to be capable of aggregating into amyloid-like fibril structures. The crystal structure of protein L5 was determined at a 1...
September 18, 2018: Applied Microbiology and Biotechnology
Pei Wang, Jonas Balko, Rui Lu, Ángela I López-Lorente, Lutz Dürselen, Boris Mizaikoff
Degeneration of human meniscal tissue induces impairment of normal knee functions, and is a highly relevant etiology of knee joint tears and osteoarthritis. Currently, the grading scale of meniscus degeneration is conventionally derived from evaluating meniscal morphology and histological staining. However, mid-infrared attenuated total reflectance (IR-ATR) spectroscopy is a particularly useful technique that may analyze the biomolecular composition at a sample surface, and provide information on the intra- and/or inter-molecular chemical bonds...
September 19, 2018: Analyst
Kristoffer Bra Nnstro M, Anna L Gharibyan, Tohidul Islam, Irina Iakovleva, Lina Nilsson, Cheng Choo Lee, Linda Sandblad, Annelie Pamren, Anders Olofsson
We demonstrate the use of Scanning Electron microscopy (SEM) in combination with Surface Plasmon Resonance (SPR) to probe and verify the formation of amyloid and its morphology on an SPR chip. SPR is a technique that measures changes in the immobilized weight on the chip surface and is frequently used to probe the formation and biophysical properties of amyloid structures. In this context it is of interest to also monitor the morphology of the formed structures. The SPR chip surface is made of a layer of gold, which represent a suitable material for direct analysis of the surface using SEM...
August 2018: Data in Brief
Weibin Gong, Wanhui Hu, Linan Xu, Huiwen Wu, Si Wu, Hong Zhang, Jinfeng Wang, Gary W Jones, Sarah Perrett
The allosteric coupling of the highly conserved nucleotide- and substrate-binding domains of Hsp70 has been studied intensively. In contrast, the role of the disordered, highly variable C-terminal region of Hsp70 remains unclear. In many eukaryotic Hsp70s, the extreme C-terminal EEVD motif binds to tetratricopeptide-repeat domains of Hsp70 co-chaperones. Here, we discovered that the TVEEVD sequence of Saccharomyces cerevisiae cytoplasmic Hsp70 (Ssa1) functions as a SUMO-interacting motif. A second C-terminal motif of ~15 amino acids between the α-helical lid and the extreme C terminus, previously identified in bacterial and eukaryotic organellar Hsp70s, is known to enhance chaperone function by transiently interacting with folding clients...
September 18, 2018: Journal of Biological Chemistry
Santu Bera, Ehud Gazit
The self-assembly of short peptide building blocks into well-ordered nanostructures is a key direction in bionanotechnology. The formation of β-sheet organizations by short peptides is well explored, leading to the development of a wide range of functional assemblies. Likewise, many natural proteinaceous materials, such as silk and amyloid fibrils, are based on β-sheet structures. In contrast, collagen, the most abundant protein in mammals, is based on helical arrangement. Similar to β-sheet structures, short helical peptides have been recently discovered to possess a diverse set of functionalities with the potential to fabricate artificial self-assembling materials...
September 17, 2018: Protein and Peptide Letters
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