301
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Evans JS. Aragonite-associated biomineralization proteins are disordered and contain interactive motifs. ACTA ACUST UNITED AC 2012; 28:3182-5. [PMID: 23060620 DOI: 10.1093/bioinformatics/bts604] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
MOTIVATION The formation of aragonite mineral in the mollusk shell or pearl nacre requires the participation of a diverse set of proteins that form the mineralized extracellular matrix. Although self-assembly processes have been identified for several nacre proteins, these proteins do not contain known globular protein-protein binding domains. Thus, we hypothesize that other sequence features are responsible for nacre matrix protein-protein assembly processes and ultimately aragonite biosynthesis. RESULTS Of 39 mollusk aragonite-associated protein sequences, 100% contain at least one region of intrinsic disorder or unfolding, with the highest percentages found in framework and pearl-associated proteins relative to the intracrystalline proteins. In some instances, these intrinsically disordered regions were identified as bind/fold sequences, and a limited number correlate with known biomineral-relevant sequences. Interestingly, 95% of the aragonite-associated protein sequences were found to contain at least one occurrence of amyloid-like or cross-β strand aggregation-prone supersecondary motifs, and this correlates with known aggregation and aragonite formation functions in three experimentally tested protein sequences. Collectively, our findings indicate that aragonite-associated proteins have evolved signature sequence traits of intrinsic disorder and aggregation-prone regions that are important for their role(s) in matrix assembly and mineralization.
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Affiliation(s)
- John Spencer Evans
- Laboratory for Chemical Physics, Department of Basic Sciences and Craniofacial Biology, New York University, New York, NY 10012, USA.
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302
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Kuroda D, Shirai H, Jacobson MP, Nakamura H. Computer-aided antibody design. Protein Eng Des Sel 2012; 25:507-21. [PMID: 22661385 PMCID: PMC3449398 DOI: 10.1093/protein/gzs024] [Citation(s) in RCA: 174] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 04/14/2012] [Accepted: 04/19/2012] [Indexed: 11/12/2022] Open
Abstract
Recent clinical trials using antibodies with low toxicity and high efficiency have raised expectations for the development of next-generation protein therapeutics. However, the process of obtaining therapeutic antibodies remains time consuming and empirical. This review summarizes recent progresses in the field of computer-aided antibody development mainly focusing on antibody modeling, which is divided essentially into two parts: (i) modeling the antigen-binding site, also called the complementarity determining regions (CDRs), and (ii) predicting the relative orientations of the variable heavy (V(H)) and light (V(L)) chains. Among the six CDR loops, the greatest challenge is predicting the conformation of CDR-H3, which is the most important in antigen recognition. Further computational methods could be used in drug development based on crystal structures or homology models, including antibody-antigen dockings and energy calculations with approximate potential functions. These methods should guide experimental studies to improve the affinities and physicochemical properties of antibodies. Finally, several successful examples of in silico structure-based antibody designs are reviewed. We also briefly review structure-based antigen or immunogen design, with application to rational vaccine development.
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Affiliation(s)
- Daisuke Kuroda
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, Japan.
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303
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Ángyán AF, Perczel A, Gáspári Z. Estimating intrinsic structural preferences of de novo emerging random-sequence proteins: is aggregation the main bottleneck? FEBS Lett 2012; 586:2468-72. [PMID: 22728433 DOI: 10.1016/j.febslet.2012.06.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 06/04/2012] [Accepted: 06/05/2012] [Indexed: 11/18/2022]
Abstract
Present-day proteins are believed to have evolved features to reduce the risk of aggregation. However, proteins can emerge de novo by translation of non-coding DNA segments. In this study we assess the aggregation, disorder and transmembrane propensity of protein sequences generated by translating random nucleotide sequences of varying GC-content. Potential de novo random-sequence proteins translated from regions with GC content between 40% and 60% do not show stronger aggregation propensity than existing ones and exhibit similar tendency to be disordered. We suggest that de novo emerging proteins do not mean an unavoidable aggregation threat to evolving organisms.
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Affiliation(s)
- Annamária F Ángyán
- Eötvös Loránd University, Institute of Chemistry, Pázmány Péter s. 1/A, H-1117 Budapest, Hungary
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304
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Meng SR, Zhu YZ, Guo T, Liu XL, Chen J, Liang Y. Fibril-forming motifs are essential and sufficient for the fibrillization of human Tau. PLoS One 2012; 7:e38903. [PMID: 22701727 PMCID: PMC3372541 DOI: 10.1371/journal.pone.0038903] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Accepted: 05/14/2012] [Indexed: 11/29/2022] Open
Abstract
Background The misfolding of amyloidogenic proteins including human Tau protein, human prion protein, and human α-synuclein is involved in neurodegenerative diseases such as Alzheimer disease, prion disease, and Parkinson disease. Although a lot of research on such amyloidogenic proteins has been done, we do not know the determinants that drive these proteins to form fibrils and thereby induce neurodegenerative diseases. In this study, we want to know the role of fibril-forming motifs from such amyloidogenic proteins in the fibrillization of human Tau protein. Methodology/Principal Findings As evidenced by thioflavin T binding and turbidity assays, transmission electron microscopy, and circular dichroism, fibril-forming motifs are essential and sufficient for the fibrillization of microtubule-associated protein Tau: only when both of its fibril-forming motifs, PHF6 and PHF6*, are deleted can recombinant human Tau fragment Tau244–372 lose its ability to form fibrils, and the insertion of unrelated fibril-forming motifs from other amyloidogenic proteins, such as human prion protein, yeast prion protein, human α-synuclein, and human amyloid β, into the disabled Tau protein can retrieve its ability to form fibrils. Furthermore, this retrieval is independent of the insertion location on Tau244–372. Conclusions/Significance We demonstrate for the first time that insertion of fibril-forming motifs can replace PHF6/PHF6* motifs, driving human Tau protein to form fibrils with different morphologies and different kinetic parameters. Our results suggest that fibril-forming motifs play a key role in the fibrillization of human Tau protein and could be the determinants of amyloidogenic proteins tending to misfold, thereby causing the initiation and development of neurodegenerative diseases. Our study also touches on the importance of amyloid “strains”: changes to the amyloidgenic driver region results in altered structural morphologies at the macromolecular level.
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Affiliation(s)
- Sheng-Rong Meng
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Ying-Zhu Zhu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Tong Guo
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiao-Ling Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jie Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yi Liang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- * E-mail:
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305
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Entzminger KC, Chang C, Myhre RO, McCallum KC, Maynard JA. The Skp chaperone helps fold soluble proteins in vitro by inhibiting aggregation. Biochemistry 2012; 51:4822-34. [PMID: 22650963 DOI: 10.1021/bi300412y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The periplasmic seventeen kilodalton protein (Skp) chaperone has been characterized primarily for its role in outer membrane protein (OMP) biogenesis, during which the jellyfish-like trimeric protein encapsulates partially folded OMPs, protecting them from the aqueous environment until delivery to the BAM outer membrane protein insertion complex. However, Skp is increasingly recognized as a chaperone that also assists in folding soluble proteins in the bacterial periplasm. In this capacity, Skp coexpression increases the active yields of many recombinant proteins and bacterial virulence factors. Using a panel of single-chain antibodies and a single-chain T-cell receptor (collectively termed scFvs) possessing varying stabilities and biophysical characteristics, we performed in vivo expression and in vitro folding and aggregation assays in the presence or absence of Skp. For Skp-sensitive scFvs, the presence of Skp during in vitro refolding assays reduced aggregation but did not alter the observed folding rates, resulting in a higher overall yield of active protein. Of the proteins analyzed, Skp sensitivity in all assays correlated with the presence of folding intermediates, as observed with urea denaturation studies. These results are consistent with Skp acting as a holdase, sequestering partially folded intermediates and thereby preventing aggregation. Because not all soluble proteins are sensitive to Skp coexpression, we hypothesize that the presence of a long-lived protein folding intermediate renders a protein sensitive to Skp. Improved understanding of the bacterial periplasmic protein folding machinery may assist in high-level recombinant protein expression and may help identify novel approaches to block bacterial virulence.
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Affiliation(s)
- Kevin C Entzminger
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, USA
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306
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Ndao M, Ponce CB, Evans JS. Oligomer formation, metalation, and the existence of aggregation-prone and mobile sequences within the intracrystalline protein family, Asprich. Faraday Discuss 2012. [DOI: 10.1039/c2fd20064c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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307
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Nair SSK, Subba Reddy NV, Hareesha KS. Exploiting heterogeneous features to improve in silico prediction of peptide status - amyloidogenic or non-amyloidogenic. BMC Bioinformatics 2011; 12 Suppl 13:S21. [PMID: 22373069 PMCID: PMC3278838 DOI: 10.1186/1471-2105-12-s13-s21] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Background Prediction of short stretches in protein sequences capable of forming amyloid-like fibrils is important in understanding the underlying cause of amyloid illnesses thereby aiding in the discovery of sequence-targeted anti-aggregation pharmaceuticals. Due to the constraints of experimental molecular techniques in identifying such motif segments, it is highly desirable to develop computational methods to provide better and affordable in silico predictions. Results Accurate in silico prediction techniques of amyloidogenic peptide regions rely on the cooperation between informative features and classifier design. In this research article, we propose one such efficient fibril prediction implementation exploiting heterogeneous features based on bio-physio-chemical (BPC) properties, auto-correlation function of carefully selected amino acid indices and atomic composition within a protein fragment of amino acids in a window. In an attempt to get an optimal number of BPC features, an evolutionary Support Vector Machine (SVM) integrating a novel implementation of hybrid Genetic Algorithm termed Memetic Algorithm and SVM is utilized. Five prediction modules designed using Artificial Neural Network (ANN) models are trained with independent and integrated features in order to validate the fibril forming motifs. The results provide evidence that incorporating new feature namely auto-correlation function besides BPC, attempt to strengthen the sequence interaction effect in forming the feature vector thereby obtaining better prediction quality in terms of sensitivity, specificity, Mathews Correlation Coefficient and Area under the Receiver Operating Characteristics curve. Conclusion A significant improvement in performance is observed by introducing features like auto-correlation function that maintains sequence order effect, in addition to the conventional BPC properties selected through a novel optimization strategy to predict the peptide status – amyloidogenic or non-amyloidogenic. The proposed approach achieves acceptable results, comparable to most online predictors. Besides, it compensates the lacuna in existing amyloid fibril prediction tools by maintaining equilibrium between sensitivity and specificity.
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Affiliation(s)
- Smitha Sunil Kumaran Nair
- Department of Computer Science and Engineering, Manipal Institute of Technology, Manipal University, Karnataka, India.
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308
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Maltsev AV, Bystryak S, Galzitskaya OV. The role of β-amyloid peptide in neurodegenerative diseases. Ageing Res Rev 2011; 10:440-52. [PMID: 21406255 DOI: 10.1016/j.arr.2011.03.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 03/03/2011] [Accepted: 03/07/2011] [Indexed: 12/27/2022]
Abstract
Studies of neurodegenerative disorders (NDDs) are drawing more attention of researchers worldwide due to the high incidence of Alzheimer's disease (AD). The pathophysiology of such disorders is, in part, characterized by the transition of a wild-type peptide from its native conformation into a very stable pathological isoform. Subsequently, these abnormal proteins form aggregates of amyloid fibrils that continuously increase in size. Changes in the metabolic processes of neurons (e.g. oxidative stress, hyperphosphorylation of the tau protein, and resulting secondary changes in the cell metabolism) ultimately lead to cell death. We hypothesize that extracellular deposition of β-amyloid peptide fibrils and neurofibrillary tangles represents the body's adaptation mechanism, aimed at preservation of autonomic functioning; while the cognitive decline is severe, the rest of the organ systems remain unaffected and continue to function. This hypothesis is supported by the fact that destruction of pathological plaques, fibrils, and tangles and the use of vaccines targeting β-amyloid result in undesirable side effects. To gain a better understanding of the pathophysiology of Alzheimer's disease and to develop novel therapies, continued studies of the sporadic form of disease and the mechanisms triggering conformational changes in β-amyloid peptide fragments are essential. This review is focused on studies investigating the formation of amyloid fibrils and their role in the pathogenesis of neurodegenerative diseases. In addition, we discuss a related disorder--amyloidosis--where formation of fibrils, tangles, and plaques leads to neuronal death which may occur as a result of a failed adaptation process. Further in-depth investigation and comprehensive analysis of alterations in the metabolism of APP, β-amyloid, and tau protein, which have a pathological effect on cell membrane, alter phosphate exchange, and impair other key metabolic functions of the cell long before the characteristic amyloid deposition takes place, is warranted. A better understanding of intraneuronal processes is crucial in identifying specific inhibitors of pathologic neuronal processes and, consequently, will allow for targeted therapy, thus maximizing efficacy of selected therapeutic regimens.
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Affiliation(s)
- A V Maltsev
- Russian Gerontological Research Clinical Center, Russian Ministry of Health Care, Moscow, Russia.
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309
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Abstract
Amyloid-related diseases are a group of illnesses in which an abnormal accumulation of proteins into fibrillar structures is evident. Results from a wide range of studies, ranging from identification of amyloid-β dimers in the brain to biophysical characterization of the interactions between amyloidogenic peptides and lipid membranes during fibril growth shed light on the initial events which take place during amyloid aggregation. Accounts of fibril disaggregation and formation of globular aggregates due to interactions with lipids or fatty acids further demonstrate the complexity of the aggregation process and the difficulty to treat amyloid-related diseases. There is an inherent difficulty in generalizing from studies of aggregation in vitro, but the involvement of too many cellular components limits the ability to follow amyloid aggregation in a cellular (or extracellular) context. Fortunately, the development of experimental methods to generate stable globular aggregates suggests new means of studying the molecular events associated with amyloid aggregation. Furthermore, simulation studies enable deeper understanding of the experimental results and provide useful predictions that can be tested in the laboratory. Computer simulations can nowadays provide molecular or even atomistic details that are experimentally not available or very difficult to obtain. In the present review, recent developments on modelling and experiments of amyloid aggregation are reviewed, and an integrative account on how isolated interactions (as observed in vitro and in silico) combine during the course of amyloid-related diseases is presented. Finally, it is argued that an integrative approach is necessary to get a better understanding of the protein aggregation process.
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310
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Galzitskaya OV. Regions which are Responsible for Swapping are also Responsible for Folding and Misfolding. Open Biochem J 2011; 5:27-36. [PMID: 21769300 PMCID: PMC3134983 DOI: 10.2174/1874091x01105010027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 05/17/2011] [Accepted: 05/28/2011] [Indexed: 12/01/2022] Open
Abstract
Domain swapping is a term used to describe a process when two or more protein chains exchange identical structural elements. Some cases of amyloid formation can be explained through a domain swapping mechanism therefore this deserves theoretical consideration and studying. It has been demonstrated that diverse proteins in sequence and structure are able to oligomerize via domain swapping. This allows us to suggest that the exchangeable regions are important in folding and misfolding processes of proteins, i.e. the residues from the swapping regions are typically incorporated into the native structure early during its formation. The modeling of folding of the proteins with swapped domains demonstrates that the regions exchanged in the oligomeric form in most cases are also responsible for folding and misfolding. For 11 out of 17 proteins, swapping regions intersect with the predicted amyloidogenic regions. Moreover, for 10 out of 17 proteins, high Φ-values (>0.5) belong to residues from the swapping regions. Our data confirm that the exchangeable regions are important in folding, misfolding, and domain swapping processes of the proteins, therefore the suggestion that domain swapping can serve as a mechanism for functional interconversion between monomers and oligomers is likely to be correct.
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Affiliation(s)
- Oxana V Galzitskaya
- Institute of Protein Research, Russian Academy of Sciences, Institutskaya str. 4, Pushchino, Moscow Region, 142290, Russia
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311
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Dual amyloid domains promote differential functioning of the chaplin proteins during Streptomyces aerial morphogenesis. Proc Natl Acad Sci U S A 2011; 108:9821-6. [PMID: 21628577 DOI: 10.1073/pnas.1018715108] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The chaplin proteins are functional amyloids found in the filamentous Streptomyces bacteria. These secreted proteins are required for the aerial development of Streptomyces coelicolor, and contribute to an intricate rodlet ultrastructure that decorates the surfaces of aerial hyphae and spores. S. coelicolor encodes eight chaplin proteins. Previous studies have revealed that only three of these proteins (ChpC, ChpE, and ChpH) are necessary for promoting aerial development, and of these three, ChpH is the primary developmental determinant. Here, we show that the model chaplin, ChpH, contains two amyloidogenic domains: one in the N terminus and one in the C terminus of the mature protein. These domains have different polymerization properties as determined using fluorescence spectroscopy, secondary structure analyses, and electron microscopy. We coupled these in vitro assays with in vivo genetic studies to probe the connection between ChpH amyloidogenesis and its biological function. Using mutational analyses, we demonstrated that both N- and C-terminal amyloid domains of ChpH were required for promoting aerial hypha formation, while the N-terminal domain was dispensable for assembly of the rodlet ultrastructure. These results suggest that there is a functional differentiation of the dual amyloid domains in the chaplin proteins.
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312
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Hamodrakas SJ. Protein aggregation and amyloid fibril formation prediction software from primary sequence: towards controlling the formation of bacterial inclusion bodies. FEBS J 2011; 278:2428-35. [DOI: 10.1111/j.1742-4658.2011.08164.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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313
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Sarkar N, Kumar M, Dubey VK. Exploring possibility of promiscuity of amyloid inhibitor: Studies on effect of selected compounds on folding and amyloid formation of proteins. Process Biochem 2011. [DOI: 10.1016/j.procbio.2011.02.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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314
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Castillo V, Graña-Montes R, Sabate R, Ventura S. Prediction of the aggregation propensity of proteins from the primary sequence: Aggregation properties of proteomes. Biotechnol J 2011; 6:674-85. [DOI: 10.1002/biot.201000331] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 02/23/2011] [Accepted: 03/03/2011] [Indexed: 12/14/2022]
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315
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Zibaee S, Fraser G, Jakes R, Owen D, Serpell LC, Crowther RA, Goedert M. Human beta-synuclein rendered fibrillogenic by designed mutations. J Biol Chem 2010; 285:38555-67. [PMID: 20833719 PMCID: PMC2992288 DOI: 10.1074/jbc.m110.160721] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 08/16/2010] [Indexed: 12/16/2022] Open
Abstract
Filamentous inclusions made of α-synuclein are found in nerve cells and glial cells in a number of human neurodegenerative diseases, including Parkinson disease, dementia with Lewy bodies, and multiple system atrophy. The assembly and spreading of these inclusions are likely to play an important role in the etiology of common dementias and movement disorders. Both α-synuclein and the homologous β-synuclein are abundantly expressed in the central nervous system; however, β-synuclein is not present in the pathological inclusions. Previously, we observed a poor correlation between filament formation and the presence of residues 73-83 of α-synuclein, which are absent in β-synuclein. Instead, filament formation correlated with the mean β-sheet propensity, charge, and hydrophilicity of the protein (global physicochemical properties) and β-strand contiguity calculated by a simple algorithm of sliding averages (local physicochemical property). In the present study, we rendered β-synuclein fibrillogenic via one set of point mutations engineered to enhance global properties and a second set engineered to enhance predominantly β-strand contiguity. Our findings show that the intrinsic physicochemical properties of synucleins influence their fibrillogenic propensity via two distinct but overlapping modalities. The implications for filament formation and the pathogenesis of neurodegenerative diseases are discussed.
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Affiliation(s)
- Shahin Zibaee
- From the Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom and
| | - Graham Fraser
- From the Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom and
| | - Ross Jakes
- From the Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom and
| | - David Owen
- From the Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom and
| | - Louise C. Serpell
- the School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom
| | - R. Anthony Crowther
- From the Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom and
| | - Michel Goedert
- From the Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom and
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