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Laursen NS, Pedersen DV, Gytz H, Zarantonello A, Bernth Jensen JM, Hansen AG, Thiel S, Andersen GR. Functional and Structural Characterization of a Potent C1q Inhibitor Targeting the Classical Pathway of the Complement System. Front Immunol 2020; 11:1504. [PMID: 32849513 PMCID: PMC7396675 DOI: 10.3389/fimmu.2020.01504] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 06/09/2020] [Indexed: 12/30/2022] Open
Abstract
The classical pathway of complement is important for protection against pathogens and in maintaining tissue homeostasis, but excessive or aberrant activation is directly linked to numerous pathologies. We describe the development and in vitro characterization of C1qNb75, a single domain antibody (nanobody) specific for C1q, the pattern recognition molecule of the classical pathway. C1qNb75 binds to the globular head modules of human C1q with sub-nanomolar affinity and impedes classical pathway mediated hemolysis by IgG and IgM. Crystal structure analysis revealed that C1qNb75 recognizes an epitope primarily located in the C1q B-chain that overlaps with the binding sites of IgG and IgM. Thus, C1qNb75 competitively prevents C1q from binding to IgG and IgM causing blockade of complement activation by the classical pathway. Overall, C1qNb75 represents a high-affinity nanobody-based inhibitor of IgG- and IgM-mediated activation of the classical pathway and may serve as a valuable reagent in mechanistic and functional studies of complement, and as an efficient inhibitor of complement under conditions of excessive CP activation.
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Affiliation(s)
- Nick S Laursen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Dennis V Pedersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Heidi Gytz
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Alessandra Zarantonello
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | | | | | - Steffen Thiel
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
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2
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Wei X, Yang D, Li H, Jiang H, Liu X, Zhang Q, Yang J. Sialic acid-binding lectins (SABLs) from Solen grandis function as PRRs ensuring immune recognition and bacterial clearance. FISH & SHELLFISH IMMUNOLOGY 2018; 72:477-483. [PMID: 29146448 DOI: 10.1016/j.fsi.2017.11.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 10/31/2017] [Accepted: 11/10/2017] [Indexed: 06/07/2023]
Abstract
Sialic acid-binding lectins (SABLs) are ubiquitous ancient molecules with binding properties to N-acetyl or N-glycolyl carbohydrates, and play crucial roles in both adaptive and innate immune responses. In present study, recombinant protein and antibodies of two SABLs from mollusk Solen grandis (SgSABL-1 and SgSABL-2) were prepared to investigate their functions in innate immunity. The recombinant protein of SgSABL-1 (rSgSABL-1) could bind LPS, PGN and β-glucan in vitro, while rSgSABL-2 could only bind PGN rather than LPS and β-glucan. Be coincident with their PAMPs recognition properties, rSgSABL-1 displayed a broad agglutination spectrum towards gram-positive bacteria Micrococcus luteus, gram-negative bacteria Listonella anguillarum and fungi Pichia pastoris, and rSgSABL-2 only showed remarkable agglutinative effect on M. luteus and L. anguillarum. More importantly, after PAMPs recognition, rSgSABL-1 and rSgSABL-2 enhanced phagocytosis as well as encapsulation ability of hemocytes in vitro, and the enhanced encapsulation could be blocked by specific antibodies. All these results indicated that SgSABL-1 and SgSABL-2 functioned as two compensative pattern-recognition receptor (PRRs) with distinct recognition spectrum and involved in the innate immune response of S. grandis.
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Affiliation(s)
- Xiumei Wei
- Laboratory of Aquatic Comparative Immunology, School of Life Sciences, East China Normal University, Shanghai, 200241, China; Shandong Marine Resource and Environment Research Institute, Yantai 264006, China
| | - Dinglong Yang
- Shandong Marine Resource and Environment Research Institute, Yantai 264006, China
| | - Huiying Li
- Laboratory of Aquatic Comparative Immunology, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Hailin Jiang
- Shandong Marine Resource and Environment Research Institute, Yantai 264006, China
| | - Xiangquan Liu
- Shandong Marine Resource and Environment Research Institute, Yantai 264006, China
| | - Qin Zhang
- Key Laboratory of Marine Biotechnology of Guangxi, Guangxi Institute of Oceanology, Beihai 536000, China.
| | - Jialong Yang
- Laboratory of Aquatic Comparative Immunology, School of Life Sciences, East China Normal University, Shanghai, 200241, China.
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Bálint M, Jeszenői N, Horváth I, van der Spoel D, Hetényi C. Systematic exploration of multiple drug binding sites. J Cheminform 2017; 9:65. [PMID: 29282592 PMCID: PMC5745209 DOI: 10.1186/s13321-017-0255-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 12/16/2017] [Indexed: 02/06/2023] Open
Abstract
Background Targets with multiple (prerequisite or allosteric) binding sites have an increasing importance in drug design. Experimental determination of atomic resolution structures of ligands weakly bound to multiple binding sites is often challenging. Blind docking has been widely used for fast mapping of the entire target surface for multiple binding sites. Reliability of blind docking is limited by approximations of hydration models, simplified handling of molecular flexibility, and imperfect search algorithms. Results To overcome such limitations, the present study introduces Wrap ‘n’ Shake (WnS), an atomic resolution method that systematically “wraps” the entire target into a monolayer of ligand molecules. Functional binding sites are extracted by a rapid molecular dynamics shaker. WnS is tested on biologically important systems such as mitogen-activated protein, tyrosine-protein kinases, key players of cellular signaling, and farnesyl pyrophosphate synthase, a target of antitumor agents.![]() Electronic supplementary material The online version of this article (10.1186/s13321-017-0255-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mónika Bálint
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pécs, Szigeti út 12, Pécs, 7624, Hungary.,Department of Biochemistry, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117, Hungary
| | - Norbert Jeszenői
- MTA NAP-B Molecular Neuroendocrinology Group, Institute of Physiology, Szentágothai Research Center, Center for Neuroscience, University of Pécs, Szigeti út 12, Pecs, 7624, Hungary
| | - István Horváth
- Chemistry Doctoral School, University of Szeged, Dugonics tér 13, Szeged, 6720, Hungary
| | - David van der Spoel
- Uppsala Center for Computational Chemistry, Science for Life Laboratory, Department of Cell and Molecular Biology, University of Uppsala, Box 596, 75124, Uppsala, Sweden
| | - Csaba Hetényi
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pécs, Szigeti út 12, Pécs, 7624, Hungary.
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4
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Zhang L, Sun W, Cai W, Zhang Z, Chen H, Ma S, Jia X. Transcriptional response of four C1q domain containing protein (C1qDC) genes from Venerupis philippinarum exposed to the water soluble fraction of No.0 diesel oil. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 132:40-46. [PMID: 27261881 DOI: 10.1016/j.ecoenv.2016.05.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/15/2016] [Accepted: 05/25/2016] [Indexed: 06/05/2023]
Abstract
As pattern recognitionreceptors, the C1q-domain-containing (C1qDC) proteins play an important role in the pathogen recognition and complement pathway activation. In the present study, four novel C1q domain containing proteins (designated as VpC1qDC1, VpC1qDC2, VpC1qDC3 and VpC1qDC4) were cloned and characterized from clam Venerupis philippinarum. The four VpC1qDCs all possessed the conserved features critical for the fundamental structure and function of the C1q family. The four VpC1qDCs genes showed differential response profiles after exposure to the water soluble fraction of No.0 diesel oil (WSFD). More notably, VpC1qDC1 and VpC1qDC3 were more sensitive to low concentration of WSFD, as their mRNA level changed by higher magnitudes. In addition, VpC1qDC2 and VpC1qDC4 displayed notable increases with larger amplitude to high concentration of WSFD. All these results suggested that the transcriptional response of VpC1qDCs genes were probably a protective mechanism of the cell to oils pollution. The diverse expression patterns of VpC1qDCs demonstrated that VpC1qDC1 and VpC1qDC3 were sensitive responders to environmental stress in V. philippinarum.
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Affiliation(s)
- Linbao Zhang
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, South China Sea Fisheries Research Institute, Guangzhou 510300, PR China; Key Laboratory of Fishery Ecology Environment, Guangdong Province, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, PR China.
| | - Wei Sun
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, South China Sea Fisheries Research Institute, Guangzhou 510300, PR China; Key Laboratory of Fishery Ecology Environment, Guangdong Province, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, PR China
| | - Wengui Cai
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, South China Sea Fisheries Research Institute, Guangzhou 510300, PR China; Key Laboratory of Fishery Ecology Environment, Guangdong Province, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, PR China
| | - Zhe Zhang
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, South China Sea Fisheries Research Institute, Guangzhou 510300, PR China; Key Laboratory of Fishery Ecology Environment, Guangdong Province, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, PR China
| | - Haigang Chen
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, South China Sea Fisheries Research Institute, Guangzhou 510300, PR China; Key Laboratory of Fishery Ecology Environment, Guangdong Province, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, PR China
| | - Shengwei Ma
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, South China Sea Fisheries Research Institute, Guangzhou 510300, PR China; Key Laboratory of Fishery Ecology Environment, Guangdong Province, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, PR China
| | - Xiaoping Jia
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, South China Sea Fisheries Research Institute, Guangzhou 510300, PR China; Key Laboratory of Fishery Ecology Environment, Guangdong Province, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, PR China.
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5
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Merle NS, Church SE, Fremeaux-Bacchi V, Roumenina LT. Complement System Part I - Molecular Mechanisms of Activation and Regulation. Front Immunol 2015; 6:262. [PMID: 26082779 PMCID: PMC4451739 DOI: 10.3389/fimmu.2015.00262] [Citation(s) in RCA: 979] [Impact Index Per Article: 108.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 05/11/2015] [Indexed: 12/12/2022] Open
Abstract
Complement is a complex innate immune surveillance system, playing a key role in defense against pathogens and in host homeostasis. The complement system is initiated by conformational changes in recognition molecular complexes upon sensing danger signals. The subsequent cascade of enzymatic reactions is tightly regulated to assure that complement is activated only at specific locations requiring defense against pathogens, thus avoiding host tissue damage. Here, we discuss the recent advances describing the molecular and structural basis of activation and regulation of the complement pathways and their implication on physiology and pathology. This article will review the mechanisms of activation of alternative, classical, and lectin pathways, the formation of C3 and C5 convertases, the action of anaphylatoxins, and the membrane-attack-complex. We will also discuss the importance of structure-function relationships using the example of atypical hemolytic uremic syndrome. Lastly, we will discuss the development and benefits of therapies using complement inhibitors.
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Affiliation(s)
- Nicolas S Merle
- UMR_S 1138, Cordeliers Research Center, Complement and Diseases Team, INSERM , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France
| | - Sarah Elizabeth Church
- UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France ; UMR_S 1138, Cordeliers Research Center, Integrative Cancer Immunology Team, INSERM , Paris , France
| | - Veronique Fremeaux-Bacchi
- UMR_S 1138, Cordeliers Research Center, Complement and Diseases Team, INSERM , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France ; Service d'Immunologie Biologique, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges-Pompidou , Paris , France
| | - Lubka T Roumenina
- UMR_S 1138, Cordeliers Research Center, Complement and Diseases Team, INSERM , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France
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6
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Yadav S, Gupta S, Selvaraj C, Doharey PK, Verma A, Singh SK, Saxena JK. In silico and in vitro studies on the protein-protein interactions between Brugia malayi immunomodulatory protein calreticulin and human C1q. PLoS One 2014; 9:e106413. [PMID: 25184227 PMCID: PMC4153637 DOI: 10.1371/journal.pone.0106413] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 07/31/2014] [Indexed: 12/20/2022] Open
Abstract
Filarial parasites modulate effective immune response of their host by releasing a variety of immunomodulatory molecules, which help in the long persistence of the parasite within the host. The present study was aimed to characterize an immunomodulatory protein of Brugia malayi and its interaction with the host immune component at the structural and functional level. Our findings showed that Brugia malayi Calreticulin (BmCRT) is responsible for the prevention of classical complement pathway activation via its interaction with the first component C1q of the human host. This was confirmed by inhibition of C1q dependent lysis of immunoglobulin-sensitized Red Blood Cells (S-RBCs). This is possibly the first report which predicts CRT-C1q interaction on the structural content of proteins to explain how BmCRT inhibits this pathway. The molecular docking of BmCRT-C1q complex indicated that C1qB chain (IgG/M and CRP binding sites on C1q) played a major role in the interaction with conserved and non-conserved regions of N and P domain of BmCRT. Out of 37 amino acids of BmCRT involved in the interaction, nine amino acids (Pro(126), Glu(132), His(147), Arg(151), His(153), Met(154), Lys(156), Ala(196) and Lys(212)) are absent in human CRT. Both ELISA and in silico analysis showed the significant role of Ca(+2) in BmCRT-HuC1q complex formation and deactivation of C1r2-C1s2. Molecular dynamics studies of BmCRT-HuC1q complex showed a deviation from ∼ 0.4 nm to ∼ 1.0 nm. CD analyses indicated that BmCRT is composed of 49.6% α helix, 9.6% β sheet and 43.6% random coil. These findings provided valuable information on the architecture and chemistry of BmCRT-C1q interaction and supported the hypothesis that BmCRT binds with huC1q at their targets (IgG/M, CRP) binding sites. This interaction enables the parasite to interfere with the initial stage of host complement activation, which might be helpful in parasites establishment. These results might be utilized for help in blocking the C1q/CRT interaction and preventing parasite infection.
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Affiliation(s)
- Sunita Yadav
- Division of Biochemistry, CSIR-Central Drug Research Institute, BS10/1, Sector 10, Jankipuram extension, Lucknow, Uttar Pradesh, India
| | - Smita Gupta
- Division of Biochemistry, CSIR-Central Drug Research Institute, BS10/1, Sector 10, Jankipuram extension, Lucknow, Uttar Pradesh, India
| | - Chandrabose Selvaraj
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Alagappa University, Karaikudi, Tamilnadu, India
| | - Pawan Kumar Doharey
- Division of Biochemistry, CSIR-Central Drug Research Institute, BS10/1, Sector 10, Jankipuram extension, Lucknow, Uttar Pradesh, India
| | - Anita Verma
- Division of Biochemistry, CSIR-Central Drug Research Institute, BS10/1, Sector 10, Jankipuram extension, Lucknow, Uttar Pradesh, India
| | - Sanjeev Kumar Singh
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Alagappa University, Karaikudi, Tamilnadu, India
| | - Jitendra Kumar Saxena
- Division of Biochemistry, CSIR-Central Drug Research Institute, BS10/1, Sector 10, Jankipuram extension, Lucknow, Uttar Pradesh, India
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Pondman KM, Sobik M, Nayak A, Tsolaki AG, Jäkel A, Flahaut E, Hampel S, ten Haken B, Sim RB, Kishore U. Complement activation by carbon nanotubes and its influence on the phagocytosis and cytokine response by macrophages. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2014; 10:1287-99. [DOI: 10.1016/j.nano.2014.02.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 02/04/2014] [Accepted: 02/24/2014] [Indexed: 12/20/2022]
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8
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Popov ME, Karlinsky DM. Search for invisible binding sites of low-molecular-weight compounds on protein molecules and prediction of inhibitory activity. Mol Biol 2013. [DOI: 10.1134/s0026893313040122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Kantardjiev AA. Quantum.Ligand.Dock: protein-ligand docking with quantum entanglement refinement on a GPU system. Nucleic Acids Res 2012; 40:W415-22. [PMID: 22669908 PMCID: PMC3394274 DOI: 10.1093/nar/gks515] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Quantum.Ligand.Dock (protein-ligand docking with graphic processing unit (GPU) quantum entanglement refinement on a GPU system) is an original modern method for in silico prediction of protein-ligand interactions via high-performance docking code. The main flavour of our approach is a combination of fast search with a special account for overlooked physical interactions. On the one hand, we take care of self-consistency and proton equilibria mutual effects of docking partners. On the other hand, Quantum.Ligand.Dock is the the only docking server offering such a subtle supplement to protein docking algorithms as quantum entanglement contributions. The motivation for development and proposition of the method to the community hinges upon two arguments-the fundamental importance of quantum entanglement contribution in molecular interaction and the realistic possibility to implement it by the availability of supercomputing power. The implementation of sophisticated quantum methods is made possible by parallelization at several bottlenecks on a GPU supercomputer. The high-performance implementation will be of use for large-scale virtual screening projects, structural bioinformatics, systems biology and fundamental research in understanding protein-ligand recognition. The design of the interface is focused on feasibility and ease of use. Protein and ligand molecule structures are supposed to be submitted as atomic coordinate files in PDB format. A customization section is offered for addition of user-specified charges, extra ionogenic groups with intrinsic pK(a) values or fixed ions. Final predicted complexes are ranked according to obtained scores and provided in PDB format as well as interactive visualization in a molecular viewer. Quantum.Ligand.Dock server can be accessed at http://87.116.85.141/LigandDock.html.
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Affiliation(s)
- Alexander A Kantardjiev
- Biophysical Chemistry Group, Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria.
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10
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Radanova M, Vasilev V, Deliyska B, Kishore U, Ikonomov V, Ivanova D. Anti-C1q autoantibodies specific against the globular domain of the C1qB-chain from patient with lupus nephritis inhibit C1q binding to IgG and CRP. Immunobiology 2011; 217:684-91. [PMID: 22209113 DOI: 10.1016/j.imbio.2011.11.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 06/29/2011] [Accepted: 11/22/2011] [Indexed: 01/27/2023]
Abstract
Lupus nephritis is one of the most severe manifestations of systemic lupus erythematosus. Higher titers of serum anti-C1q autoantibodies correlate with disease activity in patients with lupus nephritis. Anti-C1q autoantibodies have been shown to bind neo-epitopes within the collagen region of human C1q. In a preliminary study, we recently reported that the anti-C1q autoantibodies could also recognize epitopes within the globular domain (gC1q) of the C1q molecule. Here, 38 sera from patients with renal biopsy-proven lupus nephritis were screened for the presence of anti-gC1q autoantibodies, using recombinant globular head regions of individual A (ghA), B (ghB) and C (ghC) chains of human C1q. We isolated anti-gC1q autoantibodies from three selected patients. Human C1q was pre-incubated with increasing concentrations of the isolated anti-ghA, anti-ghB or anti-ghC autoantibodies and its binding to different C1q target molecules such as IgG and CRP was then evaluated. Anti-ghB, but not anti-ghA and anti-ghC autoantibodies, markedly inhibited C1q interaction with IgG as well as CRP. These results appear to suggest that the anti-ghB autoantibodies may partially induce acquired functional C1q deficiency and thus may interfere with the biological function of C1q.
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Affiliation(s)
- Maria Radanova
- Department of Biochemistry, Molecular Medicine and Nutrigenomics, Medical University - Varna, Varna, Bulgaria.
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11
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Roumenina LT, Sène D, Radanova M, Blouin J, Halbwachs-Mecarelli L, Dragon-Durey MA, Fridman WH, Fremeaux-Bacchi V. Functional complement C1q abnormality leads to impaired immune complexes and apoptotic cell clearance. THE JOURNAL OF IMMUNOLOGY 2011; 187:4369-73. [PMID: 21930969 DOI: 10.4049/jimmunol.1101749] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
C1q plays a key role in apoptotic cell and immune complex removal. Its absence contributes to the loss of tolerance toward self structures and development of autoimmunity. C1q deficiencies are extremely rare and are associated with complete lack of C1q or with secretion of surrogate C1q fragments. To our knowledge, we report the first case of a functional C1q abnormality, associated with the presence of a normal C1q molecule. Homozygous GlyB63Ser mutation was found in a patient suffering from lupus with neurologic manifestations and multiple infections. The GlyB63Ser C1q bound to Igs, pentraxins, LPSs, and apoptotic cells, similarly to C1q from healthy donors. However, the interaction of C1r(2)C1s(2) and C1 complex formation was abolished, preventing further complement activation and opsonization by C3. The mutation is located between LysB(61) and LysB(65) of C1q, suggested to form the C1r binding site. Our data infer that the binding of C1q to apoptotic cells in humans is insufficient to assure self-tolerance. The opsonization capacity of C4 and C3 fragments has to be intact to fight infections and to prevent autoimmunity.
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Affiliation(s)
- Lubka T Roumenina
- Centre de Recherche des Cordeliers, INSERM Unité Mixte de Recherche en Santé 872, 75006 Paris, France.
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12
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Complement activation by carbon nanotubes. Adv Drug Deliv Rev 2011; 63:1031-41. [PMID: 21669239 DOI: 10.1016/j.addr.2011.05.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 05/24/2011] [Accepted: 05/28/2011] [Indexed: 01/12/2023]
Abstract
Carbon nanotube interaction with an important part of the innate immune system, complement, needs to be taken into account when envisaging their use in biomedical applications. Carbon nanotubes (CNTs) and other synthetic materials are recognized by various components of the complement system in human or mammalian blood and also collectins in the lungs. Modification of the surface chemistry of CNTs alters their interactions with complement proteins and collectins. Functionalizations of CNTs which have been tested so far do not completely prevent complement activation or plasma protein binding. The interaction of the functionalized CNTs with the complement system proteins in blood may influence the adhesion of CNTs to phagocytic cells and red blood cells. Excessive activation of complement can have a harmful effect on human tissues and therefore significantly limit CNT applications in biomedicine.
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13
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Kantardjiev AA. GPU.proton.DOCK: Genuine Protein Ultrafast proton equilibria consistent DOCKing. Nucleic Acids Res 2011; 39:W223-8. [PMID: 21666258 PMCID: PMC3125792 DOI: 10.1093/nar/gkr412] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
GPU.proton.DOCK (Genuine Protein Ultrafast proton equilibria consistent DOCKing) is a state of the art service for in silico prediction of protein–protein interactions via rigorous and ultrafast docking code. It is unique in providing stringent account of electrostatic interactions self-consistency and proton equilibria mutual effects of docking partners. GPU.proton.DOCK is the first server offering such a crucial supplement to protein docking algorithms—a step toward more reliable and high accuracy docking results. The code (especially the Fast Fourier Transform bottleneck and electrostatic fields computation) is parallelized to run on a GPU supercomputer. The high performance will be of use for large-scale structural bioinformatics and systems biology projects, thus bridging physics of the interactions with analysis of molecular networks. We propose workflows for exploring in silico charge mutagenesis effects. Special emphasis is given to the interface-intuitive and user-friendly. The input is comprised of the atomic coordinate files in PDB format. The advanced user is provided with a special input section for addition of non-polypeptide charges, extra ionogenic groups with intrinsic pKa values or fixed ions. The output is comprised of docked complexes in PDB format as well as interactive visualization in a molecular viewer. GPU.proton.DOCK server can be accessed at http://gpudock.orgchm.bas.bg/.
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Affiliation(s)
- Alexander A Kantardjiev
- Biophysical Chemistry Group, Institute of Organic Chemistry, Bulgarian Academy of Sciences, and Department of Physics, Sofia University, Sofia, Bulgaria.
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Roumenina LT, Radanova M, Atanasov BP, Popov KT, Kaveri SV, Lacroix-Desmazes S, Frémeaux-Bacchi V, Dimitrov JD. Heme interacts with c1q and inhibits the classical complement pathway. J Biol Chem 2011; 286:16459-69. [PMID: 21454703 DOI: 10.1074/jbc.m110.206136] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
C1q is the recognition subunit of the first component of the classical complement pathway. It participates in clearance of immune complexes and apoptotic cells as well as in defense against pathogens. Inappropriate activation of the complement contributes to cellular and tissue damage in different pathologies, urging the need for the development of therapeutic agents that are able to inhibit the complement system. In this study, we report heme as an inhibitor of C1q. Exposure of C1q to heme significantly reduced the activation of the classical complement pathway, mediated by C-reactive protein (CRP) and IgG. Interaction analyses revealed that heme reduces the binding of C1q to CRP and IgG. Furthermore, we demonstrated that the inhibition of C1q interactions results from a direct binding of heme to C1q. Formation of complex of heme with C1q caused changes in the mechanism of recognition of IgG and CRP. Taken together, our data suggest that heme is a natural negative regulator of the classical complement pathway at the level of C1q. Heme may play a role at sites of excessive tissue damage and hemolysis where large amounts of free heme are released.
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Affiliation(s)
- Lubka T Roumenina
- Centre de Recherche des Cordeliers, Université Pierre et Marie Curie, Paris 6, UMR S 872, Paris, France.
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15
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Rybak-Smith MJ, Pondman KM, Flahaut E, Salvador-Morales C, Sim RB. Recognition of Carbon Nanotubes by the Human Innate Immune System. CARBON NANOSTRUCTURES 2011. [DOI: 10.1007/978-3-642-14802-6_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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16
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Tan LA, Yu B, Sim FCJ, Kishore U, Sim RB. Complement activation by phospholipids: the interplay of factor H and C1q. Protein Cell 2010; 1:1033-49. [PMID: 21153520 DOI: 10.1007/s13238-010-0125-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Accepted: 10/17/2010] [Indexed: 10/18/2022] Open
Abstract
Complement proteins in blood recognize charged particles. The anionic phospholipid (aPL) cardiolipin binds both complement proteins C1q and factor H. C1q is an activator of the complement classical pathway, while factor H is an inhibitor of the alternative pathway. To examine opposing effects of C1q and factor H on complement activation by aPL, we surveyed C1q and factor H binding, and complement activation by aPL, either coated on microtitre plates or in liposomes. Both C1q and factor H bound to all aPL tested, and competed directly with each other for binding. All the aPL activated the complement classical pathway, but negligibly the alternative pathway, consistent with accepted roles of C1q and factor H. However, in this system, factor H, by competing directly with C1q for binding to aPL, acts as a direct regulator of the complement classical pathway. This regulatory mechanism is distinct from its action on the alternative pathway. Regulation of classical pathway activation by factor H was confirmed by measuring C4 activation by aPL in human sera in which the C1q:factor H molar ratio was adjusted over a wide range. Thus factor H, which is regarded as a down-regulator only of the alternative pathway, has a distinct role in downregulating activation of the classical complement pathway by aPL. A factor H homologue, β2-glycoprotein-1, also strongly inhibits C1q binding to cardiolipin. Recombinant globular domains of C1q A, B and C chains bound aPL similarly to native C1q, confirming that C1q binds aPL via its globular heads.
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Affiliation(s)
- Lee Aun Tan
- MRC Immunochemistry Unit, Department of Biochemistry, University of Oxford, South Parks Rd, Oxford OX13QU, UK
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17
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Dimitrov JD, Roumenina LT, Plantier JL, Andre S, Saboulard D, Meslier Y, Planchais C, Jacquemin M, Saint-Remy JM, Atanasov BP, Kaveri SV, Lacroix-Desmazes S. A human FVIII inhibitor modulates FVIII surface electrostatics at a VWF-binding site distant from its epitope. J Thromb Haemost 2010; 8:1524-31. [PMID: 20374449 DOI: 10.1111/j.1538-7836.2010.03878.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
SUMMARY BACKGROUND BO2C11 is a human monoclonal factor (F) VIII inhibitor. When bound to the C2 domain of FVIII, the Fab fragment of BO2C11 (Fab(BO2C11)) buries a surface of C2 that contains residues participating in a binding site for von Willebrand factor (VWF). BO2C11 has thus been proposed to neutralize FVIII by steric hindrance. OBJECTIVES The BO2C11 epitope on C2 overlaps with residues located at the periphery of the putative VWF binding site; hence, most of the residues that constitute the VWF binding site on C2 and a3 remain accessible for VWF interaction following BO2C11/FVIII complex formation. We thus investigated the contribution of alternative molecular mechanisms to FVIII inactivation by BO2C11. METHODS Continuum electrostatic calculations were applied to the crystal structure of C2, free or Fab(BO2C11)-complexed. In silico predictions were confirmed by site-directed mutagenesis and VWF-binding assays of the mutated FVIII. RESULTS Binding of Fab(BO2C11) to C2 induced perturbations in the electrostatic potential of C2 and in the local electrostatic parameters of 18 charged residues in C2, which are distant from the BO2C11 epitope. Nine of the predicted electrostatic hotspots clustered on the VWF-binding site of C2. Mutation of some of the predicted electrostatic hotspots has been associated with hemophilia A and reduced VWF binding in vitro. CONCLUSIONS Inhibitors may neutralize FVIII by alteration of protein surface electrostatics at a long distance from their epitope. Perturbation of the electrostatic environment of C2, either upon binding by anti-FVIII antibodies or consecutive to missense mutations in the F8 gene, may lead to hampered VWF binding and reduced FVIII residence time in circulation.
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Affiliation(s)
- J D Dimitrov
- Centre de Recherche des Cordeliers, Université Pierre et Marie Curie - Paris6, UMR S 872, Paris, France
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18
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Kantardjiev AA, Atanasov BP. PHEMTO: protein pH-dependent electric moment tools. Nucleic Acids Res 2009; 37:W422-7. [PMID: 19420068 PMCID: PMC2703894 DOI: 10.1093/nar/gkp336] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2009] [Revised: 04/17/2009] [Accepted: 04/21/2009] [Indexed: 11/13/2022] Open
Abstract
PHEMTO (protein pH-dependent electric moment tools) is released in response to the high demand in protein science community for evaluation of electrostatic characteristics in relations to molecular recognition. PHEMTO will serve protein scientists with new advanced features for analysis of protein molecular interactions: Electric/dipole moments, their pH-dependence and in silico charge mutagenesis effects on these properties as well as alternative algorithms for electric/dipole moment computation--Singular value decomposition of electrostatic potential (EP) to account for reaction field. The implementation is based on long-term experience--PHEI mean field electrostatics and PHEPS server for evaluation of global and local pH-dependent properties. However, PHEMTO is not just an update of our PHEPS server. Besides standard electrostatics, we offer new, advanced and useful features for analysis of protein molecular interactions. In addition our algorithms are very fast. Special emphasis is given to the interface--intuitive and user-friendly. The input is comprised of the atomic coordinate file in Protein Data Bank format. The advanced user is provided with a special input section for addition of non-polypeptide charges. The output covers actually full electrostatic characteristics but special emphasis is given to electric/dipole moments and their interactive visualization. PHEMTO server can be accessed at http://phemto.orgchm.bas.bg/.
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Affiliation(s)
| | - Boris P. Atanasov
- Biophysical Chemistry Group, Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia-1113, Bulgaria
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19
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Kang YH, Tan LA, Carroll MV, Gentle ME, Sim RB. Target pattern recognition by complement proteins of the classical and alternative pathways. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 653:117-28. [PMID: 19799115 DOI: 10.1007/978-1-4419-0901-5_8] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The complement system is a major component of the innate defence of animals against invading microorganisms, and is also essential for the recognition and clearance of damaged or structurally-altered host cells or macromolecules. The system is activated by three different pathways, each of which responds, using different recognition molecules, to a very wide range of activators. The recognition protein of the complement classical pathway, C1q is described in detail here, with comparisons to the alternative pathway.
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Affiliation(s)
- Yu-Hoi Kang
- MRC Immunochemistry Unit, Department of Biochemistry, University of Oxford, Oxford, UK
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20
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Shvets VI, Kaplun AP, Krasnopol’skii YM, Stepanov AE, Chekhonin VP. From liposomes of the 1970s to 21st century nanobiotechnology. ACTA ACUST UNITED AC 2008. [DOI: 10.1134/s1995078008110013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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21
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Païdassi H, Tacnet-Delorme P, Lunardi T, Arlaud GJ, Thielens NM, Frachet P. The lectin-like activity of human C1q and its implication in DNA and apoptotic cell recognition. FEBS Lett 2008; 582:3111-6. [PMID: 18703056 DOI: 10.1016/j.febslet.2008.08.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 07/24/2008] [Accepted: 08/05/2008] [Indexed: 12/16/2022]
Abstract
C1q, the binding subunit of the C1 complex of complement, is an archetypal pattern recognition molecule known for its striking ability to recognize a wide variety of targets, ranging from pathogenic non self to altered self. DNA is one of the C1q ligands, but the precise region of C1q and the DNA motifs that support interaction have not been characterized yet. Here, we report for the first time that the peripheral globular region of the C1q molecule displays a lectin-like activity, which contributes to DNA binding through interaction with its deoxy-d-ribose moiety and may participate in apoptotic cell recognition.
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Affiliation(s)
- Helena Païdassi
- Institut de Biologie Structurale Jean-Pierre Ebel, F-38027 Grenoble Cedex 1, France
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22
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Roumenina LT, Popov KT, Bureeva SV, Kojouharova M, Gadjeva M, Rabheru S, Thakrar R, Kaplun A, Kishore U. Interaction of the globular domain of human C1q with Salmonella typhimurium lipopolysaccharide. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:1271-6. [PMID: 18513495 DOI: 10.1016/j.bbapap.2008.04.029] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 04/25/2008] [Accepted: 04/29/2008] [Indexed: 12/29/2022]
Abstract
Gram-negative bacteria can bind complement protein C1q in an antibody-independent manner and activate classical pathway via their lipopolysaccharides (LPS). Earlier studies have implicated the collagen-like region of human C1q in binding LPS. In recent years, a number of C1q target molecules, previously considered to interact with collagen-like region of C1q, have been shown to bind via the globular domain (gC1q). Here we report, using recombinant forms of the globular head regions of C1q A, B and C chains, that LPS derived from Salmonella typhimurium interact specifically with the B-chain of the gC1q domain in a calcium-dependent manner. LPS and IgG-binding sites on the gC1q domain appear to be overlapping and this interaction can be inhibited by a synthetic C1q inhibitor, suggesting common interacting mechanisms.
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Affiliation(s)
- Lubka T Roumenina
- Department of Biochemistry, Sofia University, St. Kliment Ohridski, 8 Dragan Tsankov St., Sofia 1164, Bulgaria
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