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Shahsavani MB, Hoshino M, Kumar A, Yousefi R. Charge manipulation of the human insulin B chain C-terminal to shed light on the complex mechanism of insulin fibrillation. Biochim Biophys Acta Gen Subj 2024; 1868:130578. [PMID: 38278307 DOI: 10.1016/j.bbagen.2024.130578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/13/2024] [Accepted: 01/23/2024] [Indexed: 01/28/2024]
Abstract
Insulin fibrillation poses a significant challenge in the development and treatment of diabetes. Current efforts to unravel its mechanisms have thus far remained incomplete. To shed light on the intricate processes behind insulin fibrillation, we employed mutagenesis techniques to introduce additional positive charge residues into the C-terminal region of the insulin B chain which plays an important role in insulin dimerization. We employed our investigation with various spectroscopic methods, electron microscopy, and molecular dynamics simulations. These methods allowed us to explore the structure and fibrillation behavior of the engineered B chains following their expression in a bacterial host and successful purification. This manipulation had a pronounced impact on the oligomerization behavior of the insulin B chain. It appears that these mutations delay the formation of the dimeric state in the process of transitioning to larger oligomers, consequently, leading to an alteration in the kinetics of fibrillation. Our findings also indicated that the mutant insulin B chains (Di-R, Di-K, and Di-H) displayed resistance to the initiation of fibrillation. This resistance can be attributed to the repulsive forces generated by the introduced positive charges, which disrupt the attractive interactions favoring nucleation. Notably, the mutant B chains formed shorter and less abundant oligomers and fibrils, which can be ascribed to the alterations induced by repulsion. Our engineered mutant B chains exhibited enhanced stability against stress-induced fibrillation, hinting at their potential utility in the development of new insulin analogs. This study underscores the significance of the C-terminal region in the initial stages of insulin B chain fibrillation, providing valuable insights into the intricate mechanisms involved and their potential pharmaceutical applications.
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Affiliation(s)
- Mohammad Bagher Shahsavani
- Protein Chemistry Laboratory (PCL), Department of Biology, College of Sciences, Shiraz University, Shiraz, Iran
| | - Masaru Hoshino
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Ashutosh Kumar
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Reza Yousefi
- Protein Chemistry Laboratory (PCL), Department of Biology, College of Sciences, Shiraz University, Shiraz, Iran; Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran.
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2
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Chen X, Xing L, Li X, Chen N, Liu L, Wang J, Zhou X, Liu S. Manganese Ion-Induced Amyloid Fibrillation Kinetics of Hen Egg White-Lysozyme in Thermal and Acidic Conditions. ACS OMEGA 2023; 8:16439-16449. [PMID: 37179629 PMCID: PMC10173442 DOI: 10.1021/acsomega.3c01531] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 04/18/2023] [Indexed: 05/15/2023]
Abstract
As manganese ions (Mn2+) are identified as an environmental risk factor for neurodegenerative diseases, uncovering their action mechanism on protein amyloid fibril formation is crucial for related disease treatments. Herein, we performed a combined study of Raman spectroscopy, atomic force microscopy (AFM), thioflavin T (ThT) fluorescence, and UV-vis absorption spectroscopy assays, in which the distinctive effect of Mn2+ on the amyloid fibrillation kinetics of hen egg white-lysozyme (HEWL) was clarified at the molecular level. With thermal and acid treatments, the unfolding of protein tertiary structures is efficiently accelerated by Mn2+ to form oligomers, as indicated by two Raman markers for the Trp residues on protein side chains: the FWHM at 759 cm-1 and the I1340/I1360 ratio. Meanwhile, the inconsistent evolutionary kinetics of the two indicators, as well as AFM images and UV-vis absorption spectroscopy assays, validate the tendency of Mn2+ toward the formation of amorphous aggregates instead of amyloid fibrils. Moreover, Mn2+ plays an accelerator role in the secondary structure transition from α-helix to organized β-sheet structures, as indicated by the N-Cα-C intensity at 933 cm-1 and the amide I position of Raman spectroscopy and ThT fluorescence assays. Notably, the more significant promotion effect of Mn2+ on the formation of amorphous aggregates provides credible clues to understand the fact that excess exposure to manganese is associated with neurological diseases.
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Affiliation(s)
- Xiaodong Chen
- Department
of Chemical Physics, University of Science
and Technology of China, Hefei 230026, China
| | - Lei Xing
- State
Key Laboratory of Analytical Chemistry for Life Science, School of
Chemistry and Chemical Engineering, Nanjing
University, Nanjing 210023, China
| | - Xinfei Li
- Department
of Chemical Physics, University of Science
and Technology of China, Hefei 230026, China
| | - Ning Chen
- Department
of Chemical Physics, University of Science
and Technology of China, Hefei 230026, China
| | - Liming Liu
- Department
of Chemical Physics, University of Science
and Technology of China, Hefei 230026, China
| | - Jionghan Wang
- Department
of Chemical Physics, University of Science
and Technology of China, Hefei 230026, China
| | - Xiaoguo Zhou
- Department
of Chemical Physics, University of Science
and Technology of China, Hefei 230026, China
| | - Shilin Liu
- Department
of Chemical Physics, University of Science
and Technology of China, Hefei 230026, China
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3
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Application of Amyloid-Based Hybrid Membranes in Drug Delivery. Polymers (Basel) 2023; 15:polym15061444. [PMID: 36987222 PMCID: PMC10052896 DOI: 10.3390/polym15061444] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/07/2023] [Accepted: 03/13/2023] [Indexed: 03/15/2023] Open
Abstract
The properties of amyloid fibrils, e.g., unique structural characteristics and superior biocompatibility, make them a promising vehicle for drug delivery. Here, carboxymethyl cellulose (CMC) and whey protein isolate amyloid fibril (WPI-AF) were used to synthesize amyloid-based hybrid membranes as vehicles for the delivery of cationic and hydrophobic drugs (e.g., methylene blue (MB) and riboflavin (RF)). The CMC/WPI-AF membranes were synthesized via chemical crosslinking coupled with phase inversion. The zeta potential and scanning electron microscopy results revealed a negative charge and a pleated surface microstructure with a high content of WPI-AF. FTIR analysis showed that the CMC and WPI-AF were cross-linked via glutaraldehyde and the interacting forces between membrane and MB or RF was found to be electrostatic interaction and hydrogen bonding, respectively. Next, the in vitro drug release from membranes was monitored using UV-vis spectrophotometry. Additionally, two empirical models were used to analyze the drug release data and relevant rate constant and parameters were determined accordingly. Moreover, our results indicated that in vitro drug release rates depended on the drug–matrix interactions and transport mechanism, which could be controlled by altering the WPI-AF content in membrane. This research provides an excellent example of utilizing two-dimensional amyloid-based materials for drug delivery.
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Natarajan A, Rangan K, Vadrevu R. Self-assembly of a peptide sequence, EKKE, composed of exclusively charged amino acids: Role of charge in morphology and lead binding. J Pept Sci 2023; 29:e3451. [PMID: 36098076 DOI: 10.1002/psc.3451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/14/2022] [Accepted: 09/08/2022] [Indexed: 01/12/2023]
Abstract
The self-assembly of peptides is influenced by their amino acid sequence and other factors including pH, charge, temperature, and solvent. Herein, we explore whether a four-residue sequence, EKKE, consisting of exclusively charged amino acids shows the propensity to form self-assembled ordered nanostructures and whether the overall charge plays any role in morphological and functional properties. From a combination of experimental data provided by Thioflavin T fluorescence, Congo red absorbance, circular dichroism spectroscopy, dynamic light scattering, field emission-scanning electron microscopy, atomic force microscopy, and confocal microscopy, it is clear that the all-polar peptide and charged EKKE sequence shows a pH-dependent tendency to form amyloid-like structures, and the self-assembled entities under acidic, basic and neutral conditions exhibit morphological variation. Additionally, the ability of the self-assembled amyloid nanostructures to bind to the toxic metal, lead (Pb2+ ), was demonstrated from the analysis of the ultraviolet absorbance and X-ray photoelectron spectroscopy data. The modulation at the sequence level for the amyloid-forming EKKE scaffold can further extend its potential role not only in the remediation of other toxic metals but also towards biomedical applications.
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Affiliation(s)
- Aishwarya Natarajan
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, India
| | - Krishnan Rangan
- Department of Chemistry, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, India
| | - Ramakrishna Vadrevu
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, India
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5
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Paik B, Calero-Rubio C, Lee JY, Jia X, Kiick KL, Roberts CJ. Characterizing aggregate growth and morphology of alanine-rich polypeptides as a function of sequence chemistry and solution temperature from scattering, spectroscopy, and microscopy. Biophys Chem 2020; 267:106481. [PMID: 33035751 DOI: 10.1016/j.bpc.2020.106481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 10/23/2022]
Abstract
The aggregation behavior and stability of a series of alanine-rich peptides, which are included as components of peptide-polymer conjugates, were characterized using a combination of biophysical techniques. Light scattering techniques were used to monitor changes in peptide morphology and size distributions as a function of time and temperature. The results show large particles immediately upon dissolution in buffer. At room temperature, these particles relaxed to reach a mostly monomeric peptide state, while at higher temperatures, they grew to form aggregates. Circular dichroism spectroscopy (CD) was used to monitor temperature- and time-dependent conformational changes as a function of peptide sequence and incubation time. CD measurements reveal that all of the sequences are helical at low temperatures with transitions to non-helical conformation with increased temperature. Samples incubated at room temperature were able to recover their original helicity. At increased temperature, the shorter and longer peptide sequences showed notable changes in conformation, and were not able to recover their original helicity after 72 h. After incubation for up to one week, β-sheet conformations were observed in these two cases, while only α-helical conformation loss was observed for the peptide of intermediate molecular weight. Transmission electron microscopy measurements reveal the formation of fibrils after 72 h of incubation at 60 °C for all samples, in agreement with the scattering measurements. Additional quenching experiments show that peptide aggregation can be stalled when solutions are cooled to room temperature.
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Affiliation(s)
- Bradford Paik
- Department of Material Science & Engineering Department, University of Delaware, Newark, DE 19716, United States of America
| | - Cesar Calero-Rubio
- Department of Chemical & Biomolecular Engineering, University of Delaware, Newark, DE 19716, United States of America
| | - Jee Young Lee
- Department of Material Science & Engineering Department, University of Delaware, Newark, DE 19716, United States of America
| | - Xinqiao Jia
- Department of Material Science & Engineering Department, University of Delaware, Newark, DE 19716, United States of America
| | - Kristi L Kiick
- Department of Material Science & Engineering Department, University of Delaware, Newark, DE 19716, United States of America.
| | - Christopher J Roberts
- Department of Chemical & Biomolecular Engineering, University of Delaware, Newark, DE 19716, United States of America.
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Investigating the effect of sugar-terminated nanoparticles on amyloid fibrillogenesis of β-lactoglobulin. Int J Biol Macromol 2020; 165:291-307. [PMID: 32961178 DOI: 10.1016/j.ijbiomac.2020.09.104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 08/19/2020] [Accepted: 09/14/2020] [Indexed: 11/22/2022]
Abstract
In vivo tissue deposition of fibrillar protein aggregates is the cause of several degenerative diseases. Evidence suggests that interfering with the pathology-associated amyloid fibrillogenesis by inhibitory molecules is envisaged as the primary therapeutic strategy. Amyloid fibril formation of proteins has been demonstrated to be influenced by nanoparticles/nanomaterials. As compared with their molecular form counterpart, this work examined the effect of sucrose-terminated nanoparticles on the in vitro amyloid fibrillogenesis and structural properties of β-lactoglobulin at pH 2.0 and 80 °C. ThT binding and electron microscopy results demonstrated that sucrose-terminated nanoparticles were able to suppress β-lactoglobulin fibrillogenesis in a concentration-dependent fashion. Importantly, sucrose-terminated nanoparticles showed better β-lactoglobulin fibril-inhibiting ability than sucrose molecules. ANS fluorescence and right-angle light scattering results showed reduced solvent exposure and decreased aggregation, respectively, in the β-lactoglobulin samples upon treatment with sucrose-terminated nanoparticles. Moreover, fluorescence quenching analyses revealed that the static quenching mechanism and formation of a non-fluorescent fluorophore-nanoparticle complex are involved in the nanoparticle-β-lactoglobulin interaction. We believe that the results from this study may suggest that the nanoparticle form of biocompatible sugar-related osmolytes may serve as effective inhibiting/suppressing agents toward protein fibrillogenesis.
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7
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Chao YJ, Wu K, Chang HH, Chien MJ, Chan JCC. Manifold of self-assembly of a de novo designed peptide: amyloid fibrils, peptide bundles, and fractals. RSC Adv 2020; 10:29510-29515. [PMID: 35521097 PMCID: PMC9055936 DOI: 10.1039/d0ra04480f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 08/02/2020] [Indexed: 12/18/2022] Open
Abstract
We report that a peptide with the sequence of EGAGAAAAGAGE can have different aggregation states, viz., amyloid fibrils, peptide bundles, and fractal assembly under different incubation conditions. The chemical state of the Glu residue played a pivotal regulating role in the aggregation behavior of the peptide. The mechanism of the fractal assembly of this peptide has been unraveled as follows. The peptide fragments adopting the beta-sheet conformation are well dispersed in alkaline solution. In the buffer of sodium bicarbonate, peptide rods are formed with considerable structural rigidity at the C- and N-termini. The peptide rods undergo random trajectory in the solution and form a fractal pattern on a two-dimensional surface via the diffusion-limited aggregation process.
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Affiliation(s)
- Yu-Jo Chao
- Department of Chemistry, National Taiwan University No. 1, Section 4, Roosevelt Road Taipei 10617 Taiwan
| | - Kan Wu
- Department of Chemistry, National Taiwan University No. 1, Section 4, Roosevelt Road Taipei 10617 Taiwan
| | - Hsun-Hui Chang
- Department of Chemistry, National Taiwan University No. 1, Section 4, Roosevelt Road Taipei 10617 Taiwan
| | - Ming-Jou Chien
- Department of Chemistry, National Taiwan University No. 1, Section 4, Roosevelt Road Taipei 10617 Taiwan
| | - Jerry Chun Chung Chan
- Department of Chemistry, National Taiwan University No. 1, Section 4, Roosevelt Road Taipei 10617 Taiwan
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8
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Meesaragandla B, Karanth S, Janke U, Delcea M. Biopolymer-coated gold nanoparticles inhibit human insulin amyloid fibrillation. Sci Rep 2020; 10:7862. [PMID: 32398693 PMCID: PMC7217893 DOI: 10.1038/s41598-020-64010-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 04/06/2020] [Indexed: 12/15/2022] Open
Abstract
Deposits of protein misfolding and/or aggregates are a pathological hallmark of amyloid-related diseases. For instance, insulin amyloid fibril deposits have been observed in patients with insulin-dependent diabetes mellitus after insulin administration. Here, we report on the use of AuNPs functionalized with linear- (i.e. dextrin and chitosan) and branched- (i.e. dextran-40 and dextran-10) biopolymers as potential agents to inhibit insulin fibril formation. Our dynamic light scattering analyses showed a size decrease of the amyloid fibrils in the presence of functionalized AuNPs. Circular dichroism spectroscopy as well as enzyme-linked immunosorbent assay data demonstrated that the secondary structural transition from α-helix to β-sheet (which is characteristic for insulin amyloid fibril formation) was significantly suppressed by all biopolymer-coated AuNPs, and in particular, by those functionalized with linear biopolymers. Both transmission electron microscopy and atomic force microscopy analyses showed that the long thick amyloid fibrils formed by insulin alone become shorter, thinner or cluster when incubated with biopolymer-coated AuNPs. Dextrin- and chitosan-coated AuNPs were found to be the best inhibitors of the fibril formation. Based on these results, we propose a mechanism for the inhibition of insulin amyloid fibrils: biopolymer-coated AuNPsstrongly interact with the insulin monomers and inhibit the oligomer formation as well as elongation of the protofibrils.Moreover, cytotoxicity experiments showed that AuNP-insulin amyloid fibrils are less toxic compared to insulin amyloid fibrils alone. Our results suggest that both dextrin- and chitosan-AuNPs could be used as therapeutic agents for the treatment of amyloid-related disorders.
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Affiliation(s)
- Brahmaiah Meesaragandla
- Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Straße 4, 17489, Greifswald, Germany.,ZIK HIKE - Zentrum für Innovationskompetenz, Humorale Immunreaktionen bei kardiovaskulären Erkrankungen", Fleischmannstraße 42, 17489, Greifswald, Germany
| | - Sanjai Karanth
- Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Straße 4, 17489, Greifswald, Germany.,ZIK HIKE - Zentrum für Innovationskompetenz, Humorale Immunreaktionen bei kardiovaskulären Erkrankungen", Fleischmannstraße 42, 17489, Greifswald, Germany
| | - Una Janke
- Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Straße 4, 17489, Greifswald, Germany.,ZIK HIKE - Zentrum für Innovationskompetenz, Humorale Immunreaktionen bei kardiovaskulären Erkrankungen", Fleischmannstraße 42, 17489, Greifswald, Germany
| | - Mihaela Delcea
- Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Straße 4, 17489, Greifswald, Germany. .,ZIK HIKE - Zentrum für Innovationskompetenz, Humorale Immunreaktionen bei kardiovaskulären Erkrankungen", Fleischmannstraße 42, 17489, Greifswald, Germany. .,DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung), partner site, Greifswald, Germany.
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9
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Abraham JN, Pawar P, Kootteri DK. Self‐Assembly of Di‐Guanine Peptide Nucleic Acid Amphiphiles into Fractal Patterns. ChemistrySelect 2019. [DOI: 10.1002/slct.201902677] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jancy N. Abraham
- Polymer Science and Engineering DivisionCSIR-National Chemical Laboratory Dr. Homibhabha road Pune– 411008 India
| | - Prabhakar Pawar
- Indian Institute of Science Education and Research Dr. Homibhabha road Pune– 411008 India
| | - Dilna K. Kootteri
- Polymer Science and Engineering DivisionCSIR-National Chemical Laboratory Dr. Homibhabha road Pune– 411008 India
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10
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Lu NH, How SC, Lin CY, Tsai SL, Bednarikova Z, Fedunova D, Gazova Z, Wu JW, Wang SSS. Examining the effects of dextran-based polymer-coated nanoparticles on amyloid fibrillogenesis of human insulin. Colloids Surf B Biointerfaces 2018; 172:674-683. [DOI: 10.1016/j.colsurfb.2018.09.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 08/24/2018] [Accepted: 09/12/2018] [Indexed: 10/28/2022]
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11
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Settanni G, Schäfer T, Muhl C, Barz M, Schmid F. Poly-sarcosine and Poly(Ethylene-Glycol) Interactions with Proteins Investigated Using Molecular Dynamics Simulations. Comput Struct Biotechnol J 2018; 16:543-550. [PMID: 30524669 PMCID: PMC6259037 DOI: 10.1016/j.csbj.2018.10.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/22/2018] [Accepted: 10/23/2018] [Indexed: 11/23/2022] Open
Abstract
Nanoparticles coated with hydrophilic polymers often show a reduction in unspecific interactions with the biological environment, which improves their biocompatibility. The molecular determinants of this reduction are not very well understood yet, and their knowledge may help improving nanoparticle design. Here we address, using molecular dynamics simulations, the interactions of human serum albumin, the most abundant serum protein, with two promising hydrophilic polymers used for the coating of therapeutic nanoparticles, poly(ethylene-glycol) and poly-sarcosine. By simulating the protein immersed in a polymer-water mixture, we show that the two polymers have a very similar affinity for the protein surface, both in terms of the amount of polymer adsorbed and also in terms of the type of amino acids mainly involved in the interactions. We further analyze the kinetics of adsorption and how it affects the polymer conformations. Minor differences between the polymers are observed in the thickness of the adsorption layer, that are related to the different degree of flexibility of the two molecules. In comparison poly-alanine, an isomer of poly-sarcosine known to self-aggregate and induce protein aggregation, shows a significantly larger affinity for the protein surface than PEG and PSar, which we show to be related not to a different patterns of interactions with the protein surface, but to the different way the polymer interacts with water.
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Affiliation(s)
| | - Timo Schäfer
- Institut für Physik, Johannes Gutenberg University, Mainz, Germany
| | - Christian Muhl
- Institut für Organische Chemie, Johannes Gutenberg University, Mainz, Germany
| | - Matthias Barz
- Institut für Organische Chemie, Johannes Gutenberg University, Mainz, Germany
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12
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Hussain R, Zubair H, Pursell S, Shahab M. Neurodegenerative Diseases: Regenerative Mechanisms and Novel Therapeutic Approaches. Brain Sci 2018; 8:E177. [PMID: 30223579 PMCID: PMC6162719 DOI: 10.3390/brainsci8090177] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/03/2018] [Accepted: 09/12/2018] [Indexed: 12/12/2022] Open
Abstract
Regeneration refers to regrowth of tissue in the central nervous system. It includes generation of new neurons, glia, myelin, and synapses, as well as the regaining of essential functions: sensory, motor, emotional and cognitive abilities. Unfortunately, regeneration within the nervous system is very slow compared to other body systems. This relative slowness is attributed to increased vulnerability to irreversible cellular insults and the loss of function due to the very long lifespan of neurons, the stretch of cells and cytoplasm over several dozens of inches throughout the body, insufficiency of the tissue-level waste removal system, and minimal neural cell proliferation/self-renewal capacity. In this context, the current review summarized the most common features of major neurodegenerative disorders; their causes and consequences and proposed novel therapeutic approaches.
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Affiliation(s)
- Rashad Hussain
- Center for Translational Neuromedicine, University of Rochester, NY 14642, USA.
| | - Hira Zubair
- Department of Animal Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan.
| | - Sarah Pursell
- Center for Translational Neuromedicine, University of Rochester, NY 14642, USA.
| | - Muhammad Shahab
- Department of Animal Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan.
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13
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Arginine-α, β-dehydrophenylalanine Dipeptide Nanoparticles for pH-Responsive Drug Delivery. Pharm Res 2018; 35:35. [PMID: 29362936 DOI: 10.1007/s11095-017-2299-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Accepted: 11/01/2017] [Indexed: 12/26/2022]
Abstract
PURPOSE Nanoparticles (NPs) exhibiting responsiveness towards pH variations in organs, tissue microenvironments and cellular compartments can significantly add on to the drug delivery potential. Here, we have developed NPs from an amphipathic dipeptide, Arginine-α, β-dehydrophenylalanine (RΔF), and tried to explore their pH responsive drug delivery potential in various cancer cells. METHODS RΔF-NPs were architectured by harnessing the process of molecular self-assembly followed by the assessment of effect of pH on NPs morphology using zetasizer, SEM and CD. FTIR and PXRD analysis of the dipeptide and doxorubicin (Dox) were carried out for compatibility assessment followed by encapsulation of Dox in RΔF-NPs. RΔF-Dox-NPs were evaluated for pH dependent release as well as for in-vitro cellular internalization and efficacy in cancer cells. RESULTS RΔF self-assembled to form monodispersed particles at pH 7. SEM analysis revealed a loss of overall particle morphology along with particle aggregation at highly acidic and basic pH respectively. The NPs demonstrated a slow and sustained release behaviour at pH 7 (97.64 ± 4.71% after 36 h) in comparison to pH 2 (90.27 ± 1.45% after 8 h) and pH 10 (96.39 ± 3.87% after 12 h). In-vitro efficacy studies carried-out in various cancer cells revealed that RΔF-Dox-NPs exhibited higher efficacy with 1.65, 1.95 and 13.34 fold lower IC50 values in comparison to Dox in C6, HCT-116 and AGS cell lines. CONCLUSIONS RΔF-Dox-NPs with higher drug release at acidic pH, enhanced internalization in cancer cells along with higher cytotoxic potential can act as effective pH responsive drug delivery systems.
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14
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Edwards-Gayle CJC, Greco F, Hamley IW, Rambo RP, Reza M, Ruokolainen J, Skoulas D, Iatrou H. Self-Assembly of Telechelic Tyrosine End-Capped PEO Star Polymers in Aqueous Solution. Biomacromolecules 2017; 19:167-177. [DOI: 10.1021/acs.biomac.7b01420] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
| | - Francesca Greco
- School of Chemistry, Food
Biosciences and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K
| | - Ian W. Hamley
- School of Chemistry, Food
Biosciences and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K
| | - Robert P. Rambo
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K
| | - Mehedi Reza
- Department of Applied Physics, Aalto School of Science, P.O. Box 15100, FI-00076 Aalto, Finland
| | - Janne Ruokolainen
- Department of Applied Physics, Aalto School of Science, P.O. Box 15100, FI-00076 Aalto, Finland
| | - Dimitrios Skoulas
- Department of Chemistry, University of Athens, Panepistimiopolis
Zografou, 157 71 Athens, Greece
| | - Hermis Iatrou
- Department of Chemistry, University of Athens, Panepistimiopolis
Zografou, 157 71 Athens, Greece
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15
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Farrell S, DiGuiseppi D, Alvarez N, Schweitzer-Stenner R. The interplay of aggregation, fibrillization and gelation of an unexpected low molecular weight gelator: glycylalanylglycine in ethanol/water. SOFT MATTER 2016; 12:6096-6110. [PMID: 27363780 DOI: 10.1039/c6sm00879h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Hydrogels formed by polypeptides could be much-favored tools for drug delivery because their main ingredients are generally biodegradable. However, the gelation of peptides in aqueous solution generally requires a minimal length of the peptide as well as distinct sequences of hydrophilic and hydrophobic residues. The aggregation of short peptides like tripeptides, which are relatively cheap and offer a high degree of biodegradability, are generally thought to require a high hydrophobicity of their residues. We found that contrary to this expectation cationic glycylalanylglycine in 55 mol% ethanol/45 mol% water forms a gel below a melting temperature of ca. 36 °C. A pure hydrogel state can be obtained after allowing the ethanol component to evaporate. The gel phase consists of crystalline fibrils of several 100 μm, which form a sample-spanning network. Rheological data reveal a soft elastic solid gel. We investigated the kinetics of the various processes that lead to the final gel state of the ternary mixture by a unique combination of UV circular dichroism, infrared, vibrational circular dichroism (VCD) and rheological measurements. A mathematical analysis of our data show that gelation is preceded by the formation of peptide β-sheet like tapes or ribbons, which give rise to a significant enhancement of the amide I' VCD signal, and the subsequent formation of rather thick and long fibrils. The VCD signals indicate that the tapes exhibit a right-handed helicity at temperatures above 16 °C and a left-handed helicity below. The tapes'/ribbons' helicity change occurs at a temperature where the UVCD data reflect a relatively long nucleation process. The kinetics of gel formation probed by the storage and loss moduli are composed of a fast process that follows tape/ribbon/fibril formation and is clearly identifiable in a movie that shows the gelation process and a slow process that causes an additional gel stabilization. The rheological data indicate that left-handed fibrils observed at low temperatures form a more solid-like structure than their right-handed counterparts formed at higher temperatures. Taken together our data reveal GAG as an unexpected gelator, the formation of which is underlied by a set of distinguishable kinetic processes.
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Affiliation(s)
- Stefanie Farrell
- Department of Chemistry, Drexel University, Philadelphia, PA 19104, USA.
| | - David DiGuiseppi
- Department of Chemistry, Drexel University, Philadelphia, PA 19104, USA.
| | - Nicolas Alvarez
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA 19104, USA
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16
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Vanhalle M, Corneillie S, Smet M, Van Puyvelde P, Goderis B. Poly(alanine): Structure and Stability of the d and l-Enantiomers. Biomacromolecules 2015; 17:183-91. [DOI: 10.1021/acs.biomac.5b01301] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Maja Vanhalle
- Polymer
Chemistry and Materials, Department of Chemistry, KU Leuven, Celestijnenlaan
200F, Leuven, 3001, Belgium
| | - Stijn Corneillie
- Polymer
Chemistry and Materials, Department of Chemistry, KU Leuven, Celestijnenlaan
200F, Leuven, 3001, Belgium
| | - Mario Smet
- Polymer
Chemistry and Materials, Department of Chemistry, KU Leuven, Celestijnenlaan
200F, Leuven, 3001, Belgium
| | - Peter Van Puyvelde
- Soft
Matter, Applied Rheology and Technology, Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, Leuven, 3001, Belgium
| | - Bart Goderis
- Polymer
Chemistry and Materials, Department of Chemistry, KU Leuven, Celestijnenlaan
200F, Leuven, 3001, Belgium
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17
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Tang FHM, Maggi F. Reconstructing the fractal dimension of granular aggregates from light intensity spectra. SOFT MATTER 2015; 11:9150-9159. [PMID: 26414181 DOI: 10.1039/c5sm01885d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
There has been growing interest in using the fractal dimension to study the hierarchical structures of soft materials after realising that fractality is an important property of natural and engineered materials. This work presents a method to quantify the internal architecture and the space-filling capacity of granular fractal aggregates by reconstructing the three-dimensional capacity dimension from their two-dimensional optical projections. Use is made of the light intensity of the two-dimensional aggregate images to describe the aggregate surface asperities (quantified by the perimeter-based fractal dimension) and the internal architecture (quantified by the capacity dimension) within a mathematical framework. This method was tested on control aggregates of diffusion-limited (DLA), cluster-cluster (CCA) and self-correlated (SCA) types, stereolithographically-fabricated aggregates, and experimentally-acquired natural sedimentary aggregates. Statistics of the reconstructed capacity dimension featured correlation coefficients R ≥ 98%, residuals NRMSE ≤ 10% and percent errors PE ≤ 4% as compared to controls, and improved earlier approaches by up to 50%.
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Affiliation(s)
- Fiona H M Tang
- Laboratory for Environmental Engineering, School of Civil Engineering, The University of Sydney, Bld. J05, 2006 Sydney, NSW, Australia.
| | - Federico Maggi
- Laboratory for Environmental Engineering, School of Civil Engineering, The University of Sydney, Bld. J05, 2006 Sydney, NSW, Australia.
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18
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Murphy RM. Q&A: repeat-containing proteins. Nat Struct Mol Biol 2015; 22:943-5. [DOI: 10.1038/nsmb.3135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Dendritic Peptide Nanostructures Formed from Self-Assembly of Di-l-phenylalanine Extracted from Alzheimer’s β-Amyloid Poly Peptides: Insights into Their Assembly Process. Int J Pept Res Ther 2015. [DOI: 10.1007/s10989-015-9468-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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20
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Mao Y, Teoh CL, Yang S, Zlatic CO, Rosenes ZK, Gooley PR, Howlett GJ, Griffin MDW. Charge and charge-pair mutations alter the rate of assembly and structural properties of apolipoprotein C-II amyloid fibrils. Biochemistry 2015; 54:1421-8. [PMID: 25609257 DOI: 10.1021/bi5014535] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The misfolding, aggregation, and accumulation of proteins as amyloid fibrils is a defining characteristic of several debilitating diseases. Human apolipoprotein C-II (apoC-II) amyloid fibrils are representative of the fibrils formed by a number of plasma apolipoproteins implicated in amyloid-related disease. Previous structural analyses identified a buried charge pair between residues K30 and D69 within apoC-II amyloid fibrils. We have investigated the effects of amino acid substitutions of these residues on apoC-II fibril formation. Two point mutations of apoC-II, D69K and K30D, as well as a reversed ion-pair mutant containing both mutations (KDDK) were generated. Fibril formation by the double mutant, apoC-II KDDK, and apoC-II D69K was enhanced compared to that of wild-type (WT) apoC-II, while apoC-II K30D lacked the ability to form fibrils under standard conditions. Structural analyses showed that WT apoC-II, apoC-II D69K, and apoC-II KDDK fibrils have similar secondary structures and morphologies. Size distribution analyses revealed that apoC-II D69K fibrils have a broader range of fibril sizes while apoC-II KDDK fibrils showed an increased frequency of closed fibrillar loops. ApoC-II D69K fibrils exhibited reduced thioflavin T binding capacity compared to that of fibrils formed by WT apoC-II and apoC-II KDDK. These results indicate that specific charge and charge-pair mutations within apoC-II significantly alter the ability to form fibrils and that position 69 within apoC-II plays a key role in the rate-limiting step of apoC-II fibril formation.
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Affiliation(s)
- Yu Mao
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne , Parkville, Victoria 3010, Australia
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21
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Involvement of non-polyalanine (polyA) residues in aggregation of polyA proteins: Clue for inhibition of aggregation. Comput Biol Chem 2014; 53PB:318-323. [PMID: 25462338 DOI: 10.1016/j.compbiolchem.2014.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 11/11/2014] [Accepted: 11/11/2014] [Indexed: 11/21/2022]
Abstract
Presence of polyalanine (polyA) stretches in some proteins is found to be associated with their aggregation, which causes disorders in various developmental processes. In this work, inherent propensities towards aggregation of some residues, which are not part of the polyA stretches, have been identified by using the primary sequences of seven polyA proteins with the help of Betascan, PASTA and Tango programs and explored unambiguously. This provides a basis for proposing molecular mechanism of this type of aggregation. Reported suppression of aggregation of polyA proteins by chaperones like HSP40 and HSP70 is substantiated through molecular docking. The hydrophobic residues of identified aggregating region are found to be interacting with hydrophobic surface of chaperones. This suggests a crucial clue for possible way to inhibit the aggregation of such proteins.
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22
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Nag M, Bera K, Basak S. Intermolecular disulfide bond formation promotes immunoglobulin aggregation: investigation by fluorescence correlation spectroscopy. Proteins 2014; 83:169-77. [PMID: 25371040 DOI: 10.1002/prot.24715] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 10/21/2014] [Accepted: 10/28/2014] [Indexed: 11/06/2022]
Abstract
Protein aggregation generally results from association between hydrophobic regions of individual monomers. However, additional mechanisms arising from specific interactions, such as intermolecular disulfide bond formation, may also contribute to the process. The latter is proposed to be the initiating pathway for aggregation of immunoglobulin (IgG), which is essential for triggering its immune response. To test the veracity of this hypothesis, we have employed fluorescence correlation spectroscopy to measure the kinetics of aggregation of IgG in separate experiments either allowing or inhibiting disulfide formation. Fluorescence correlation spectroscopy measurements yielded a diffusion time (τ(D)) of ∼200 µsec for Rhodamine-labeled IgG, corresponding to a hydrodynamic radius (R(H)) of 56 Å for the IgG monomer. The aggregation kinetics of the protein was followed by monitoring the time evolution of τ(D) under conditions in which its cysteine residues were either free or blocked. In both cases, the progress curves confirmed that aggregation proceeded via the nucleation-dependent polymerization pathway. However, for aggregation in the presence of free cysteines, the lag times were shorter, and the aggregate sizes bigger, than their respective counterparts for aggregation in the presence of blocked cysteines. This result clearly demonstrates that formation of intermolecular disulfide bonds represents a preferred pathway in the aggregation process of IgG. Fluorescence spectroscopy showed that aggregates formed in experiments where disulfide formation was prevented denatured at lower concentration of guanidine hydrochloride than those obtained in experiments where the disulfides were free to form, indicating that intermolecular disulfide bridging is a valid pathway for IgG aggregation.
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Affiliation(s)
- Moupriya Nag
- Chemical Sciences Division, Saha Institute of Nuclear Physics, Bidhannagar, Kolkata, 700064, India
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23
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Mu Y, Yu M. Effects of hydrophobic interaction strength on the self-assembled structures of model peptides. SOFT MATTER 2014; 10:4956-4965. [PMID: 24888420 DOI: 10.1039/c4sm00378k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Stable and ordered self-assembled peptide nanostructures are formed as a result of cooperative effects of various relatively weak intermolecular interactions. We systematically studied the influence of hydrophobic interaction strength and temperature on the self-assembly of peptides with a coarse-grained model by Monte Carlo simulations. The simulation results show a rich phase behavior of peptide self-assembly, indicating that the formation and morphology of peptide assemblies may be tuned by varying the temperature and the strength of hydrophobic interactions. There exist optimal combinations of temperature and hydrophobic interaction strength where ordered fibrillar nanostructures are readily formed. Our simulation results not only facilitate the understanding of the self-assembly behavior of peptides at the molecular level, but also provide useful insights into the development of fabrication strategies for high-quality peptide fibrils.
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Affiliation(s)
- Yan Mu
- College of Materials Science and Engineering, South China University of Technology, Guangzhou, Guangdong, China.
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24
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Korolkov VV, Allen S, Roberts CJ, Tendler SJB. Surface mediated L-phenylalanyl-L-phenylalanine assembly into large dendritic structures. Faraday Discuss 2014; 166:257-67. [PMID: 24611281 DOI: 10.1039/c3fd00065f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We report a new class of dipeptide dendritic structures fabricated on the surface of mica via spin casting and the conditions required to achieve them. Both their structure and formation mechanism have been investigated in detail using Atomic Force Microscopy (AFM) at the nanometre scale. Formation of nanotubular structures and their further interaction is shown to be a key step in dendritic structure growth. A possible candidate for the primary building block in the nanotubular structure has been identified. The dendritic structures were found to be stable in ambient conditions for several months, however, they transform into needle-like crystals upon exposure to 100% (relative humidity) humid air.
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25
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Mu Y, Tang B, Yu M. Length-dependent β-sheet growth mechanisms of polyalanine peptides in water and on hydrophobic surfaces. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:032711. [PMID: 24730878 DOI: 10.1103/physreve.89.032711] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Indexed: 06/03/2023]
Abstract
Fibrillar assemblies by peptides are becoming one of the most promising nanomaterials due to their exceptional properties. The self-assembly of peptides into β sheets is a critical step in the fibrillization pathway. We investigated the length-dependent β-sheet growth mechanisms of polyalanine [poly(A)] peptides consisting of 6 to 24 alanines (A6 to A24) in water and on the hydrophobic surface, respectively, by molecular dynamics simulations. β-sheet growth behavior in water fits negative exponential growth model, showing that β-sheet growth rate decays exponentially with time. Meanwhile, increasing chain length leads to an accelerated decay of the β-sheet growth rate. By contrast, β-sheet growth on the surface from A6 to A18 occurs in two consecutive stages, both of which fit linear growth models. β-sheet growth rate in the first stage increases as chain length is increased, while the intermediate length peptide A12 has the highest β-sheet growth rate in the second stage. β-sheet growth behavior of A24 on the surface still fits negative exponential model. Overall, the hydrophobic surface accelerates β-sheet growth by enhancing local concentration and reducing conformational entropy of poly(A) peptide, and the β-sheet growth of the intermediate length peptide A12 is the fastest on the surface. Our simulation results shed light on understanding the accelerated peptide fibrillization on the hydrophobic surface.
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Affiliation(s)
- Yan Mu
- College of Materials Science and Engineering, South China University of Technology, Guangzhou Guangdong, 510641, China
| | - Binqing Tang
- College of Materials Science and Engineering, South China University of Technology, Guangzhou Guangdong, 510641, China
| | - Meng Yu
- College of Materials Science and Engineering, South China University of Technology, Guangzhou Guangdong, 510641, China
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26
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Reichheld SE, Muiznieks LD, Stahl R, Simonetti K, Sharpe S, Keeley FW. Conformational transitions of the cross-linking domains of elastin during self-assembly. J Biol Chem 2014; 289:10057-68. [PMID: 24550393 DOI: 10.1074/jbc.m113.533893] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Elastin is the intrinsically disordered polymeric protein imparting the exceptional properties of extension and elastic recoil to the extracellular matrix of most vertebrates. The monomeric precursor of elastin, tropoelastin, as well as polypeptides containing smaller subsets of the tropoelastin sequence, can self-assemble through a colloidal phase separation process called coacervation. Present understanding suggests that self-assembly is promoted by association of hydrophobic domains contained within the tropoelastin sequence, whereas polymerization is achieved by covalent joining of lysine side chains within distinct alanine-rich, α-helical cross-linking domains. In this study, model elastin polypeptides were used to determine the structure of cross-linking domains during the assembly process and the effect of sequence alterations in these domains on assembly and structure. CD temperature melts indicated that partial α-helical structure in cross-linking domains at lower temperatures was absent at physiological temperature. Solid-state NMR demonstrated that β-strand structure of the cross-linking domains dominated in the coacervate state, although α-helix was predominant after subsequent cross-linking of lysine side chains with genipin. Mutation of lysine residues to hydrophobic amino acids, tyrosine or alanine, leads to increased propensity for β-structure and the formation of amyloid-like fibrils, characterized by thioflavin-T binding and transmission electron microscopy. These findings indicate that cross-linking domains are structurally labile during assembly, adapting to changes in their environment and aggregated state. Furthermore, the sequence of cross-linking domains has a dramatic effect on self-assembly properties of elastin-like polypeptides, and the presence of lysine residues in these domains may serve to prevent inappropriate ordered aggregation.
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Affiliation(s)
- Sean E Reichheld
- From the Molecular Structure and Function Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario M5G 1X8 and
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27
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Chen L, Chen T, Fang W, Wen Y, Lin S, Lin J, Cai C. Synthesis and pH-Responsive “Schizophrenic” Aggregation of a Linear-Dendron-Like Polyampholyte Based on Oppositely Charged Polypeptides. Biomacromolecules 2013; 14:4320-30. [DOI: 10.1021/bm401215w] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lili Chen
- Shanghai Key Laboratory of
Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials
of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Tao Chen
- Shanghai Key Laboratory of
Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials
of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Wenxiang Fang
- Shanghai Key Laboratory of
Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials
of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Ying Wen
- Shanghai Key Laboratory of
Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials
of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Shaoliang Lin
- Shanghai Key Laboratory of
Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials
of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Jiaping Lin
- Shanghai Key Laboratory of
Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials
of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Chunhua Cai
- Shanghai Key Laboratory of
Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials
of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
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28
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Hughes JN, Thomas PQ. Molecular pathology of polyalanine expansion disorders: new perspectives from mouse models. Methods Mol Biol 2013; 1017:135-51. [PMID: 23719913 DOI: 10.1007/978-1-62703-438-8_10] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Disease-causing polyalanine (PA) expansion mutations have been identified in nine genes, eight of which encode transcription factors (TFs) with important roles in development. In vitro and cell overexpression studies have shown that expanded PA tracts result in protein misfolding and the formation of aggregates. This feature of PA proteins is reminiscent of the related polyglutamine (PQ) disease proteins, which have been shown to cause disease via a gain-of-function (GOF) mechanism. However, in sharp contrast to PQ disorders, the disease phenotypes associated with PA mutations are more consistent with a LOF and/or mild GOF mechanism, suggesting that their molecular pathology is inherently different to PQ disorders. Elucidating the cellular impact of PA mutations in vivo has been difficult to address as, unlike the late-onset polyglutamine disorders, all PA disorders associated with TF gene mutations are congenital. However, in recent years, significant advances have been made through the analysis of engineered (knock-in) and spontaneous PA mouse models. Here we review these recent findings and propose an updated model of the molecular and cellular mechanism of PA disorders that incorporates both LOF and GOF features.
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Affiliation(s)
- James N Hughes
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia
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29
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Sun S, Xu S, Zhang W, Wu P, Zhang W, Zhu X. Cooperative self-assembly and crystallization into fractal patterns by PNIPAM-based nonlinear multihydrophilic block copolymers under alkaline conditions. Polym Chem 2013. [DOI: 10.1039/c3py00682d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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30
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Purification and characterization of a new alkali-thermostable lipase from Staphylococcus aureus isolated from Arachis hypogaea rhizosphere. Process Biochem 2012. [DOI: 10.1016/j.procbio.2012.02.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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31
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Baker PJ, Numata K. Chemoenzymatic Synthesis of Poly(l-alanine) in Aqueous Environment. Biomacromolecules 2012; 13:947-51. [PMID: 22380731 DOI: 10.1021/bm201862z] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Peter James Baker
- Enzyme Research Team, RIKEN Biomass Engineering Program, RIKEN, 2-1 Hirosawa, Wako-shi, 351-0198 Saitama,
Japan
| | - Keiji Numata
- Enzyme Research Team, RIKEN Biomass Engineering Program, RIKEN, 2-1 Hirosawa, Wako-shi, 351-0198 Saitama,
Japan
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32
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Lee CH, Li P. pH-induced formation of various hierarchical structures from amphiphilic core–shell nanotubes. RSC Adv 2012. [DOI: 10.1039/c2ra00959e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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33
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Bernacki JP, Murphy RM. Length-dependent aggregation of uninterrupted polyalanine peptides. Biochemistry 2011; 50:9200-11. [PMID: 21932820 DOI: 10.1021/bi201155g] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Polyalanine (polyA) is the third-most prevalent homopeptide repeat in eukaryotes, behind polyglutamine and polyasparagine. Abnormal expansion of the polyA repeat is linked to at least nine human diseases, and the disease mechanism likely involves enhanced length-dependent aggregation. Because of the simplicity of its side chain, polyA has been a favorite target of computational studies, and because of their tendency to fold into α-helix, peptides containing polyA-rich domains have been a popular experimental subject. However, experimental studies on uninterrupted polyA are very limited. We synthesized polyA peptides containing uninterrupted sequences of 7 to 25 alanines (A7 to A25) and characterized their length-dependent conformation and aggregation properties. The peptides were primarily disordered, with a modest component of α-helix that increased with increasing length. From measurements of mean distance spanned by the polyA segment, we concluded that physiological buffers are neutral solvents for shorter polyA peptides and poor solvents for longer peptides. At moderate concentration and near-physiological temperature, polyA assembled into soluble oligomers, with a sharp transition in oligomer physical properties between A19 and A25. With A19, oligomers were large, contained only a small fraction of the total peptide mass, and slowly grew into loose clusters, while A25 rapidly and completely assembled into small stable oligomers of ~7 nm radius. At high temperatures, A19 assembled into fibrils, but A25 precipitated as dense, micrometer-sized particles. A comparison of these results to those obtained with polyglutamine peptides of similar design sheds light on the role of the side chain in regulating conformation and aggregation.
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Affiliation(s)
- Joseph P Bernacki
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
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34
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Vila Verde A, Beltramo PJ, Maranas JK. Adsorption of homopolypeptides on gold investigated using atomistic molecular dynamics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:5918-5926. [PMID: 21488613 DOI: 10.1021/la104814z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We investigate the role of dynamics on adsorption of peptides to gold surfaces using all-atom molecular dynamics simulations in explicit solvent. We choose six homopolypeptides [Ala(10), Ser(10), Thr(10), Arg(10), Lys(10), and Gln(10)], for which experimental surface coverages are not correlated with amino acid level affinities for gold, with the idea that dynamic properties may also play a role. To assess dynamics we determine both conformational movement and flexibility of the peptide within a given conformation. Low conformational movement indicates stability of a given conformation and leads to less adsorption than homopolypeptides with faster conformational movement. Likewise, low flexibility within a given conformation also leads to less adsorption. Neither amino acid affinities nor dynamic considerations alone predict surface coverage; rather both quantities must be considered in peptide adsorption to gold surfaces.
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Affiliation(s)
- Ana Vila Verde
- University of Minho, Department of Physics, Braga, Portugal
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35
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Teoh CL, Bekard IB, Asimakis P, Griffin MDW, Ryan TM, Dunstan DE, Howlett GJ. Shear flow induced changes in apolipoprotein C-II conformation and amyloid fibril formation. Biochemistry 2011; 50:4046-57. [PMID: 21476595 DOI: 10.1021/bi2002482] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The misfolding and self-assembly of proteins into amyloid fibrils that occur in several debilitating diseases are affected by a variety of environmental factors, including mechanical factors associated with shear flow. We examined the effects of shear flow on amyloid fibril formation by human apolipoprotein C-II (apoC-II). Shear fields (150, 300, and 500 s(-1)) accelerated the rate of apoC-II fibril formation (1 mg/mL) approximately 5-10-fold. Fibrils produced at shear rates of 150 and 300 s(-1) were similar to the twisted ribbon fibrils formed in the absence of shear, while at 500 s(-1), tangled ropelike structures were observed. The mechanism of the shear-induced acceleration of amyloid fibril formation was investigated at low apoC-II concentrations (50 μg/mL) where fibril formation does not occur. Circular dichroism and tryptophan fluorescence indicated that shear induced an irreversible change in apoC-II secondary structure. Fluorescence resonance energy transfer experiments using the single tryptophan residue in apoC-II as the donor and covalently attached acceptors showed that shear flow increased the distance between the donor and acceptor molecules. Shear-induced higher-order oligomeric species were identified by sedimentation velocity experiments using fluorescence detection, while fibril seeding experiments showed that species formed during shear flow are on the fibril formation pathway. These studies suggest that physiological shear flow conditions and conditions experienced during protein manufacturing can exert significant effects on protein conformation, leading to protein misfolding, aggregation, and amyloid fibril formation.
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Affiliation(s)
- Chai Lean Teoh
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
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Mao X, Wang C, Ma X, Zhang M, Liu L, Zhang L, Niu L, Zeng Q, Yang Y, Wang C. Molecular level studies on binding modes of labeling molecules with polyalanine peptides. NANOSCALE 2011; 3:1592-1599. [PMID: 21283870 DOI: 10.1039/c0nr00782j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this work, the binding modes of typical labeling molecules (thioflavin T (ThT), Congo red (CR) and copper(II) phthalocyanine tetrasulfonic acid tetrasodium salt (PcCu(SO(3)Na)(4))) on pentaalanine, which is a model peptide segment of amyloid peptides, have been resolved at the molecular level by using scanning tunneling microscopy (STM). In the STM images, ThT molecules are predominantly adsorbed parallel to the peptide strands and two binding modes could be identified. It was found that ThT molecules are preferentially binding on top of the peptide strand, and the mode of intercalated between neighboring peptides also exists. The parallel binding mode of CR molecules can be observed with pentaalanine peptides. Besides the binding modes of labeling molecules, the CR and PcCu(SO(3)Na)(4) display different adsorption affinity with the pentaalanine peptides. The results could be beneficial for obtaining molecular level insight of the interactions between labeling molecules and peptides.
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Affiliation(s)
- Xiaobo Mao
- National Center for Nanoscience and Technology, Beijing, 100190, China
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Han TH, Oh JK, Lee GJ, Pyun SI, Kim SO. Hierarchical assembly of diphenylalanine into dendritic nanoarchitectures. Colloids Surf B Biointerfaces 2010; 79:440-5. [DOI: 10.1016/j.colsurfb.2010.05.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Revised: 05/01/2010] [Accepted: 05/03/2010] [Indexed: 11/15/2022]
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Hamley IW, Brown GD, Castelletto V, Cheng G, Venanzi M, Caruso M, Placidi E, Aleman C, Revilla-López G, Zanuy D. Self-Assembly of a Designed Amyloid Peptide Containing the Functional Thienylalanine Unit. J Phys Chem B 2010; 114:10674-83. [DOI: 10.1021/jp105508g] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- I. W. Hamley
- School of Chemistry, Food and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Chemical Sciences and Technologies, CNR, Department of Physics, University of Rome Tor Vergata, Via Ricerca Scientifica 1, Rome, Italy, Departament d’Enginyeria Química, E. T. S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Spain, and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici
| | - G. D. Brown
- School of Chemistry, Food and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Chemical Sciences and Technologies, CNR, Department of Physics, University of Rome Tor Vergata, Via Ricerca Scientifica 1, Rome, Italy, Departament d’Enginyeria Química, E. T. S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Spain, and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici
| | - V. Castelletto
- School of Chemistry, Food and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Chemical Sciences and Technologies, CNR, Department of Physics, University of Rome Tor Vergata, Via Ricerca Scientifica 1, Rome, Italy, Departament d’Enginyeria Química, E. T. S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Spain, and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici
| | - G. Cheng
- School of Chemistry, Food and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Chemical Sciences and Technologies, CNR, Department of Physics, University of Rome Tor Vergata, Via Ricerca Scientifica 1, Rome, Italy, Departament d’Enginyeria Química, E. T. S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Spain, and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici
| | - M. Venanzi
- School of Chemistry, Food and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Chemical Sciences and Technologies, CNR, Department of Physics, University of Rome Tor Vergata, Via Ricerca Scientifica 1, Rome, Italy, Departament d’Enginyeria Química, E. T. S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Spain, and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici
| | - M. Caruso
- School of Chemistry, Food and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Chemical Sciences and Technologies, CNR, Department of Physics, University of Rome Tor Vergata, Via Ricerca Scientifica 1, Rome, Italy, Departament d’Enginyeria Química, E. T. S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Spain, and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici
| | - E. Placidi
- School of Chemistry, Food and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Chemical Sciences and Technologies, CNR, Department of Physics, University of Rome Tor Vergata, Via Ricerca Scientifica 1, Rome, Italy, Departament d’Enginyeria Química, E. T. S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Spain, and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici
| | - C. Aleman
- School of Chemistry, Food and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Chemical Sciences and Technologies, CNR, Department of Physics, University of Rome Tor Vergata, Via Ricerca Scientifica 1, Rome, Italy, Departament d’Enginyeria Química, E. T. S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Spain, and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici
| | - G. Revilla-López
- School of Chemistry, Food and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Chemical Sciences and Technologies, CNR, Department of Physics, University of Rome Tor Vergata, Via Ricerca Scientifica 1, Rome, Italy, Departament d’Enginyeria Química, E. T. S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Spain, and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici
| | - D. Zanuy
- School of Chemistry, Food and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K., Department of Chemical Sciences and Technologies, CNR, Department of Physics, University of Rome Tor Vergata, Via Ricerca Scientifica 1, Rome, Italy, Departament d’Enginyeria Química, E. T. S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Spain, and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici
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Naito M, Kishihara K, Okahata Y. Vertically aligned multilayer films of monodispersed helical polypeptides with micrometer thickness via simple cast. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:9166-9169. [PMID: 20481619 DOI: 10.1021/la1008973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Utilizing the zwitterionic alpha-helix peptide bearing a cationic and anionic group at the N- and C-terminus, respectively, we first demonstrated that the vertically aligned multilayer film can be prepared by a simple cast and slow evaporation. The tilt angle of the peptide remained unchanged with ca. 30 degrees in the range between submicrometer and several micrometers in thickness. The key designs allowing simple vertical alignment of the helical peptide multilayer films were (i) monodispersity of the peptide, (ii) electrostatic interaction between anionic substrate and the cationic group bearing at the N-terminus of the peptide, and (iii) interlayer electrostatic interaction among terminal groups of the peptide.
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Affiliation(s)
- Masanobu Naito
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan.
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Hamley IW, Castelletto V, Moulton CM, Rodríguez-Pérez J, Squires AM, Eralp T, Held G, Hicks MR, Rodger A. Alignment of a Model Amyloid Peptide Fragment in Bulk and at a Solid Surface. J Phys Chem B 2010; 114:8244-54. [DOI: 10.1021/jp101374e] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Daude N, Wohlgemuth S, Rogaeva E, Farid AH, Heaton M, Westaway D. Frequent missense and insertion/deletion polymorphisms in the ovine Shadoo gene parallel species-specific variation in PrP. PLoS One 2009; 4:e6538. [PMID: 19657386 PMCID: PMC2716538 DOI: 10.1371/journal.pone.0006538] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Accepted: 07/15/2009] [Indexed: 11/18/2022] Open
Abstract
Background The cellular prion protein PrPC is encoded by the Prnp gene. This protein is expressed in the central nervous system (CNS) and serves as a precursor to the misfolded PrPSc isoform in prion diseases. The prototype prion disease is scrapie in sheep, and whereas Prnp exhibits common missense polymorphisms for V136A, R154H and Q171R in ovine populations, genetic variation in mouse Prnp is limited. Recently the CNS glycoprotein Shadoo (Sho) has been shown to resemble PrPC both in a central hydrophobic domain and in activity in a toxicity assay performed in cerebellar neurons. Sho protein levels are reduced in prion infections in rodents. Prompted by these properties of the Sho protein we investigated the extent of natural variation in SPRN. Principal Findings Paralleling the case for ovine versus human and murine PRNP, we failed to detect significant coding polymorphisms that alter the mature Sho protein in a sample of neurologically normal humans, or in diverse strains of mice. However, ovine SPRN exhibited 4 missense mutations and expansion/contraction in a series of 5 tandem Ala/Gly-containing repeats R1-R5 encoding Sho's hydrophobic domain. A Val71Ala polymorphism and polymorphic expansion of wt 67(Ala)3Gly70 to 67(Ala)5Gly72 reached frequencies of 20%, with other alleles including Δ67–70 and a 67(Ala)6Gly73 expansion. Sheep V71, A71, Δ67–70 and 67(Ala)6Gly73 SPRN alleles encoded proteins with similar stability and posttranslational processing in transfected neuroblastoma cells. Significance Frequent coding polymorphisms are a hallmark of the sheep PRNP gene and our data indicate a similar situation applies to ovine SPRN. Whether a common selection pressure balances diversity at both loci remains to be established.
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Affiliation(s)
- Nathalie Daude
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Serene Wohlgemuth
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Ekaterina Rogaeva
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - A. Hossein Farid
- Department of Animal Science, Nova Scotia Agricultural College, Truro, Nova Scotia, Canada
| | - Mike Heaton
- United States Department of Agriculture, U. S. Meat Animal Research Center, Clay Center, Nebraska, United States of America
| | - David Westaway
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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Nojima J, Oma Y, Futai E, Sasagawa N, Kuroda R, Turk B, Ishiura S. Biochemical analysis of oligomerization of expanded polyalanine repeat proteins. J Neurosci Res 2009; 87:2290-6. [DOI: 10.1002/jnr.22052] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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How do surfactants and DTT affect the size, dynamics, activity and growth of soluble lysozyme aggregates? Biochem J 2009; 415:275-88. [PMID: 18549353 DOI: 10.1042/bj20071499] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The early intermediates in the protein aggregation pathway, the elusive soluble aggregates, play a pivotal role in growth and maturation of ordered aggregates such as amyloid fibrils. Blocking the growth of soluble oligomers is an effective strategy to inhibit aggregation. To decipher the molecular mechanisms and develop better strategies to arrest aggregation, it is imperative to understand how the size, molecular dynamics, activity and growth kinetics of soluble aggregates are affected when aggregation is inhibited. With this objective, in the present study we have investigated the influence of additives such as SDS, CTAB (cetyltrimethylammonium bromide) and DTT (dithiothreitol) on the slow aggregation of HEWL (hen eggwhite lysozyme) at pH 12.2. For this purpose, techniques such as steady-state and time-resolved fluorescence anisotropy of covalently labelled dansyl probe, gel-filtration chromatography, estimation of free thiol groups, thioflavin T and ANS (8-anilinonaphthalene-1-sulfonic acid) fluorescence, CD and atomic-force microscopy were employed to monitor the soluble oligomers over a period spanning 30 days. The results of the present study reveal that: (i) the spontaneous formation of soluble aggregates is irreversible and abolishes activity; (ii) the initial growth of aggregates (0-24 h) is promoted by a gradual increase in the exposure of hydrophobic surfaces; (iii) subsequently intermolecular disulfide bonds are critical for the assembly and stability of aggregates; (iv) the tight molecular packing inside large aggregates which contributed to slow (approximately 5 ns) and restricted segmental motion of dansyl probe was clearly loosened up in the presence of additives, enabling fast (1-2 ns) and free motion (unlike DTT, the size of lysozyme complexes with surfactants, was large, due to a conglomeration of proteins and surfactants); (v) the aggregates show reduced helical content compared with native lysozyme, except in the presence of SDS; and (vi) DTT was more potent than SDS/CTAB in arresting the growth of aggregates.
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Herczenik E, Gebbink MFBG. Molecular and cellular aspects of protein misfolding and disease. FASEB J 2008; 22:2115-33. [PMID: 18303094 DOI: 10.1096/fj.07-099671] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Proteins are essential elements for life. They are building blocks of all organisms and the operators of cellular functions. Humans produce a repertoire of at least 30,000 different proteins, each with a different role. Each protein has its own unique sequence and shape (native conformation) to fulfill its specific function. The appearance of incorrectly shaped (misfolded) proteins occurs on exposure to environmental changes. Protein misfolding and the subsequent aggregation is associated with various, often highly debilitating, diseases for which no sufficient cure is available yet. In the first part of this review we summarize the structural composition of proteins and the current knowledge of underlying forces that lead proteins to lose their native structure. In the second and third parts we describe the molecular and cellular mechanisms that are associated with protein misfolding in disease. Finally, in the last part we portray recent efforts to develop treatments for protein misfolding diseases.
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Affiliation(s)
- Eszter Herczenik
- Laboratory of Thrombosis and Haemostasis, Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
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Klein AF, Ebihara M, Alexander C, Dicaire MJ, Sasseville AMJ, Langelier Y, Rouleau GA, Brais B. PABPN1 polyalanine tract deletion and long expansions modify its aggregation pattern and expression. Exp Cell Res 2008; 314:1652-66. [PMID: 18367172 DOI: 10.1016/j.yexcr.2008.02.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Revised: 02/07/2008] [Accepted: 02/07/2008] [Indexed: 10/22/2022]
Abstract
Expansions of a (GCN)10/polyalanine tract in the Poly(A) Binding Protein Nuclear 1 (PABPN1) cause autosomal dominant oculopharyngeal muscular dystrophy (OPMD). In OPMD muscles, as in models, PABPN1 accumulates in intranuclear inclusions (INIs) whereas in other diseases caused by similar polyalanine expansions, the mutated proteins have been shown to abnormally accumulate in the cytoplasm. This study presents the impact on the subcellular localization of PABPN1 produced by large expansions or deletion of its polyalanine tract. Large tracts of more than 24 alanines result in the nuclear accumulation of PABPN1 in SFRS2-positive functional speckles and a significant decline in cell survival. These large expansions do not cause INIs formation nor do they lead to cytoplasmic accumulation. Deletion of the polyalanine tract induces the formation of aggregates that are located on either side and cross the nuclear membrane, highlighting the possible role of the N-terminal polyalanine tract in PABPN1 nucleo-cytoplasmic transport. We also show that even though five other proteins with polyalanine tracts tend to aggregate when over-expressed they do not co-aggregate with PABPN1 INIs. This study presents the first experimental evidence that there may be a relative loss of function in OPMD by decreasing the availability of PABPN1 through an INI-independent mechanism.
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Affiliation(s)
- Arnaud F Klein
- Laboratory of neurogenetics of motion, Centre d'excellence en neuromique de l'Université de Montréal, CRCHUM, Université de Montréal, Montréal, Canada
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Wang SSS, Wu JW, Yamamoto S, Liu HS. Diseases of protein aggregation and the hunt for potential pharmacological agents. Biotechnol J 2008; 3:165-92. [DOI: 10.1002/biot.200700065] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Gerstman BS, Chapagain PP. Self-organizing dynamics in protein folding. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2008; 84:1-37. [PMID: 19121698 DOI: 10.1016/s0079-6603(08)00401-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Bernard S Gerstman
- Department of Physics, Florida International University, Miami, Florida 33199, USA
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Stewart ME, Motala MJ, Yao J, Thompson LB, Nuzzo RG. Unconventional methods for forming nanopatterns. ACTA ACUST UNITED AC 2007. [DOI: 10.1243/17403499jnn103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Nanostructured materials have become an increasingly important theme in research, in no small part due to the potential impacts this science holds for applications in technology, including such notable areas as sensors, medicine, and high-performance integrated circuits. Conventional methods, such as the top-down approaches of projection lithography and scanning beam lithography, have been the primary means for patterning materials at the nanoscale. This article provides an overview of unconventional methods - both top-down and bottom-up approaches - for generating nanoscale patterns in a variety of materials, including methods that can be applied to fragile molecular systems that are difficult to pattern using conventional lithographic techniques. The promise, recent progress, advantages, limitations, and challenges to future development associated with each of these unconventional lithographic techniques will be discussed with consideration given to their potential for use in large-scale manufacturing.
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Affiliation(s)
- M. E. Stewart
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - M. J. Motala
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Jimin Yao
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - L. B. Thompson
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - R. G. Nuzzo
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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Auer S, Dobson CM, Vendruscolo M. Characterization of the nucleation barriers for protein aggregation and amyloid formation. HFSP JOURNAL 2007; 1:137-46. [PMID: 19404419 DOI: 10.2976/1.2760023] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Accepted: 06/25/2007] [Indexed: 11/19/2022]
Abstract
Despite the complexity and the specificity of the amino acid code, a variety of peptides and proteins unrelated in sequence and function exhibit a common behavior and assemble into highly organized amyloid fibrils. The formation of such aggregates is often described by a nucleation and growth mechanism, in which the proteins involved also form intermediate oligomeric aggregates before they reorganize and grow into ordered fibrils with a characteristic cross-beta structure. It is extremely difficult to experimentally obtain an accurate description of the early stages of this phenomenon due to the transient nature and structural heterogeneity of the oligomeric precursors. We investigate here the phenomenon of ordered aggregation by using the recently introduced tube model of polypeptide chains in conjunction with the generic hypothesis of amyloid formation. Under conditions where oligomer formation is a rare event-the most common conditions for forming amyloid fibrils by experiment-we calculate directly the nucleation barriers associated with oligomer formation and conversion into cross-beta structure in order to reveal the nature of these species, determine the critical nuclei, and characterize their dependence on the hydrophobicity of the peptides and the thermodynamic parameters associated with aggregation and amyloid formation.
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Affiliation(s)
- Stefan Auer
- Department of Chemistry, Cambridge University, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
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