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Wang P, Fredj Z, Zhang H, Rong G, Bian S, Sawan M. Blocking Superantigen-Mediated Diseases: Challenges and Future Trends. J Immunol Res 2024; 2024:2313062. [PMID: 38268531 PMCID: PMC10807946 DOI: 10.1155/2024/2313062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/15/2023] [Accepted: 12/30/2023] [Indexed: 01/26/2024] Open
Abstract
Superantigens are virulence factors secreted by microorganisms that can cause various immune diseases, such as overactivating the immune system, resulting in cytokine storms, rheumatoid arthritis, and multiple sclerosis. Some studies have demonstrated that superantigens do not require intracellular processing and instated bind as intact proteins to the antigen-binding groove of major histocompatibility complex II on antigen-presenting cells, resulting in the activation of T cells with different T-cell receptor Vβ and subsequent overstimulation. To combat superantigen-mediated diseases, researchers have employed different approaches, such as antibodies and simulated peptides. However, due to the complex nature of superantigens, these approaches have not been entirely successful in achieving optimal therapeutic outcomes. CD28 interacts with members of the B7 molecule family to activate T cells. Its mimicking peptide has been suggested as a potential candidate to block superantigens, but it can lead to reduced T-cell activity while increasing the host's infection risk. Thus, this review focuses on the use of drug delivery methods to accurately target and block superantigens, while reducing the adverse effects associated with CD28 mimic peptides. We believe that this method has the potential to provide an effective and safe therapeutic strategy for superantigen-mediated diseases.
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Affiliation(s)
- Pengbo Wang
- CenBRAIN Neurotech, School of Engineering, Westlake University, Hangzhou 310030, China
| | - Zina Fredj
- CenBRAIN Neurotech, School of Engineering, Westlake University, Hangzhou 310030, China
| | - Hongyong Zhang
- CenBRAIN Neurotech, School of Engineering, Westlake University, Hangzhou 310030, China
| | - Guoguang Rong
- CenBRAIN Neurotech, School of Engineering, Westlake University, Hangzhou 310030, China
| | - Sumin Bian
- CenBRAIN Neurotech, School of Engineering, Westlake University, Hangzhou 310030, China
| | - Mohamad Sawan
- CenBRAIN Neurotech, School of Engineering, Westlake University, Hangzhou 310030, China
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2
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Heyne M, Shirian J, Cohen I, Peleg Y, Radisky ES, Papo N, Shifman JM. Climbing Up and Down Binding Landscapes through Deep Mutational Scanning of Three Homologous Protein-Protein Complexes. J Am Chem Soc 2021; 143:17261-17275. [PMID: 34609866 PMCID: PMC8532158 DOI: 10.1021/jacs.1c08707] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Protein-protein interactions (PPIs) have evolved to display binding affinities that can support their function. As such, cognate and noncognate PPIs could be highly similar structurally but exhibit huge differences in binding affinities. To understand this phenomenon, we study three homologous protease-inhibitor PPIs that span 9 orders of magnitude in binding affinity. Using state-of-the-art methodology that combines protein randomization, affinity sorting, deep sequencing, and data normalization, we report quantitative binding landscapes consisting of ΔΔGbind values for the three PPIs, gleaned from tens of thousands of single and double mutations. We show that binding landscapes of the three complexes are strikingly different and depend on the PPI evolutionary optimality. We observe different patterns of couplings between mutations for the three PPIs with negative and positive epistasis appearing most frequently at hot-spot and cold-spot positions, respectively. The evolutionary trends observed here are likely to be universal to other biological complexes in the cell.
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Affiliation(s)
- Michael Heyne
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel.,Avram and Stella Goldstein-Goren Department of Biotechnology Engineering and the National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, 8410501, Israel
| | - Jason Shirian
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Itay Cohen
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering and the National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, 8410501, Israel
| | - Yoav Peleg
- Life Sciences Core Facilities (LSCF) Structural Proteomics Unit (SPU), Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Evette S Radisky
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Jacksonville, Florida 32224, United States
| | - Niv Papo
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering and the National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, 8410501, Israel
| | - Julia M Shifman
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
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3
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Fernández-Quintero ML, Kroell KB, Heiss MC, Loeffler JR, Quoika PK, Waibl F, Bujotzek A, Moessner E, Georges G, Liedl KR. Surprisingly Fast Interface and Elbow Angle Dynamics of Antigen-Binding Fragments. Front Mol Biosci 2020; 7:609088. [PMID: 33330636 PMCID: PMC7732698 DOI: 10.3389/fmolb.2020.609088] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 10/21/2020] [Indexed: 12/14/2022] Open
Abstract
Fab consist of a heavy and light chain and can be subdivided into a variable (V H and V L ) and a constant region (C H 1 and C L ). The variable region contains the complementarity-determining region (CDR), which is formed by six hypervariable loops, shaping the antigen binding site, the paratope. Apart from the CDR loops, both the elbow angle and the relative interdomain orientations of the V H -V L and the C H 1-C L domains influence the shape of the paratope. Thus, characterization of the interface and elbow angle dynamics is essential to antigen specificity. We studied nine antigen-binding fragments (Fab) to investigate the influence of affinity maturation, antibody humanization, and different light-chain types on the interface and elbow angle dynamics. While the CDR loops reveal conformational transitions in the micro-to-millisecond timescale, both the interface and elbow angle dynamics occur on the low nanosecond timescale. Upon affinity maturation, we observe a substantial rigidification of the V H and V L interdomain and elbow-angle flexibility, reflected in a narrower and more distinct distribution. Antibody humanization describes the process of grafting non-human CDR loops onto a representative human framework. As the antibody framework changes upon humanization, we investigated if both the interface and the elbow angle distributions are changed or shifted. The results clearly showed a substantial shift in the relative V H -V L distributions upon antibody humanization, indicating that different frameworks favor distinct interface orientations. Additionally, the interface and elbow angle dynamics of five antibody fragments with different light-chain types are included, because of their strong differences in elbow angles. For these five examples, we clearly see a high variability and flexibility in both interface and elbow angle dynamics, highlighting the fact that Fab interface orientations and elbow angles interconvert between each other in the low nanosecond timescale. Understanding how the relative interdomain orientations and the elbow angle influence antigen specificity, affinity, and stability has broad implications in the field of antibody modeling and engineering.
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Affiliation(s)
- Monica L. Fernández-Quintero
- Center for Molecular Biosciences Innsbruck (CMBI), Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Katharina B. Kroell
- Center for Molecular Biosciences Innsbruck (CMBI), Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Martin C. Heiss
- Center for Molecular Biosciences Innsbruck (CMBI), Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Johannes R. Loeffler
- Center for Molecular Biosciences Innsbruck (CMBI), Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Patrick K. Quoika
- Center for Molecular Biosciences Innsbruck (CMBI), Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Franz Waibl
- Center for Molecular Biosciences Innsbruck (CMBI), Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Alexander Bujotzek
- Roche Pharma Research and Early Development, Large Molecule Research, Roche Innovation Center Munich, Penzberg, Germany
| | - Ekkehard Moessner
- Roche Pharma Research and Early Development, Large Molecular Research, Roche Innovation Center Zurich, Schlieren, Switzerland
| | - Guy Georges
- Roche Pharma Research and Early Development, Large Molecule Research, Roche Innovation Center Munich, Penzberg, Germany
| | - Klaus R. Liedl
- Center for Molecular Biosciences Innsbruck (CMBI), Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
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4
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Etter D, Schelin J, Schuppler M, Johler S. Staphylococcal Enterotoxin C-An Update on SEC Variants, Their Structure and Properties, and Their Role in Foodborne Intoxications. Toxins (Basel) 2020; 12:E584. [PMID: 32927913 PMCID: PMC7551944 DOI: 10.3390/toxins12090584] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 12/20/2022] Open
Abstract
Staphylococcal enterotoxins are the most common cause of foodborne intoxications (staphylococcal food poisoning) and cause a wide range of diseases. With at least six variants staphylococcal enterotoxin C (SEC) stands out as particularly diverse amongst the 25 known staphylococcal enterotoxins. Some variants present unique and even host-specific features. Here, we review the role of SEC in human and animal health with a particular focus on its role as a causative agent for foodborne intoxications. We highlight structural features unique to SEC and its variants, particularly, the emetic and superantigen activity, as well as the roles of SEC in mastitis and in dairy products. Information about the genetic organization as well as regulatory mechanisms including the accessory gene regulator and food-related stressors are provided.
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Affiliation(s)
- Danai Etter
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, 8057 Zürich, Switzerland;
- Laboratory of Food Microbiology, Institute of Food, Nutrition and Health, ETH Zürich, 8092 Zürich, Switzerland;
| | - Jenny Schelin
- Division of Applied Microbiology, Department of Chemistry, Lund University, 22100 Lund, Sweden;
| | - Markus Schuppler
- Laboratory of Food Microbiology, Institute of Food, Nutrition and Health, ETH Zürich, 8092 Zürich, Switzerland;
| | - Sophia Johler
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, 8057 Zürich, Switzerland;
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5
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Aharon L, Aharoni SL, Radisky ES, Papo N. Quantitative mapping of binding specificity landscapes for homologous targets by using a high-throughput method. Biochem J 2020; 477:1701-1719. [PMID: 32296833 PMCID: PMC7376575 DOI: 10.1042/bcj20200188] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/11/2020] [Accepted: 04/14/2020] [Indexed: 01/08/2023]
Abstract
To facilitate investigations of protein-protein interactions (PPIs), we developed a novel platform for quantitative mapping of protein binding specificity landscapes, which combines the multi-target screening of a mutagenesis library into high- and low-affinity populations with sophisticated next-generation sequencing analysis. Importantly, this method generates accurate models to predict affinity and specificity values for any mutation within a protein complex, and requires only a few experimental binding affinity measurements using purified proteins for calibration. We demonstrated the utility of the approach by mapping quantitative landscapes for interactions between the N-terminal domain of the tissue inhibitor of metalloproteinase 2 (N-TIMP2) and three matrix metalloproteinases (MMPs) having homologous structures but different affinities (MMP-1, MMP-3, and MMP-14). The binding landscapes for N-TIMP2/MMP-1 and N-TIMP2/MMP-3 showed the PPIs to be almost fully optimized, with most single mutations giving a loss of affinity. In contrast, the non-optimized PPI for N-TIMP2/MMP-14 was reflected in a wide range of binding affinities, where single mutations exhibited a far more attenuated effect on the PPI. Our new platform reliably and comprehensively identified not only hot- and cold-spot residues, but also specificity-switch mutations that shape target affinity and specificity. Thus, our approach provides a methodology giving an unprecedentedly rich quantitative analysis of the binding specificity landscape, which will broaden the understanding of the mechanisms and evolutionary origins of specific PPIs and facilitate the rational design of specific inhibitors for structurally similar target proteins.
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Affiliation(s)
- Lidan Aharon
- Department of Biotechnology Engineering and the National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Shay-Lee Aharoni
- Department of Biotechnology Engineering and the National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Evette S. Radisky
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Jacksonville 32224, Florida, USA
| | - Niv Papo
- Department of Biotechnology Engineering and the National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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6
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Affiliation(s)
- Razvan C. Stan
- Immunology DepartmentUniversity of São Paulo Brazil
- Cantacuzino Military-Medical Research-Development National Institute, Bucharest Romania
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7
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Kaur H, Sain N, Mohanty D, Salunke DM. Deciphering evolution of immune recognition in antibodies. BMC STRUCTURAL BIOLOGY 2018; 18:19. [PMID: 30563492 PMCID: PMC6299584 DOI: 10.1186/s12900-018-0096-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 11/14/2018] [Indexed: 11/29/2022]
Abstract
Background Antibody, the primary effector molecule of the immune system, evolves after initial encounter with the antigen from a precursor form to a mature one to effectively deal with the antigen. Antibodies of a lineage diverge through antigen-directed isolated pathways of maturation to exhibit distinct recognition potential. In the context of evolution in immune recognition, diversity of antigen cannot be ignored. While there are reports on antibody lineage, structural perspective with respect to diverse recognition potential in a lineage has never been studied. Hence, it is crucial to evaluate how maturation leads to topological tailoring within a lineage enabling them to interact with significantly distinct antigens. Results A data-driven approach was undertaken for the study. Global experimental mouse and human antibody-antigen complex structures from PDB were compiled into a coherent database of germline-linked antibodies bound with distinct antigens. Structural analysis of all lineages showed variations in CDRs of both H and L chains. Observations of conformational adaptation made from analysis of static structures were further evaluated by characterizing dynamics of interaction in two lineages, mouse VH1–84 and human VH5–51. Sequence and structure analysis of the lineages explained that somatic mutations altered the geometries of individual antibodies with common structural constraints in some CDRs. Additionally, conformational landscape obtained from molecular dynamics simulations revealed that incoming pathogen led to further conformational divergence in the paratope (as observed across datasets) even while maintaining similar overall backbone topology. MM-GB/SA analysis showed binding energies to be in physiological range. Results of the study are coherent with experimental observations. Conclusions The findings of this study highlight basic structural principles shaping the molecular evolution of a lineage for significantly diverse antigens. Antibodies of a lineage follow different developmental pathways while preserving the imprint of the germline. From the study, it can be generalized that structural diversification of the paratope is an outcome of natural selection of a conformation from an available ensemble, which is further optimized for antigen interaction. The study establishes that starting from a common lineage, antibodies can mature to recognize a wide range of antigens. This hypothesis can be further tested and validated experimentally. Electronic supplementary material The online version of this article (10.1186/s12900-018-0096-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Harmeet Kaur
- Regional Centre for Biotechnology, Biotech Science Cluster, Faridabad, Haryana, 121001, India.,Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Neetu Sain
- National Institute of Immunology, New Delhi, Delhi, 110067, India
| | - Debasisa Mohanty
- National Institute of Immunology, New Delhi, Delhi, 110067, India
| | - Dinakar M Salunke
- Regional Centre for Biotechnology, Biotech Science Cluster, Faridabad, Haryana, 121001, India. .,International Centre for Genetic Engineering and Biotechnology, New Delhi, Delhi, 110067, India.
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8
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Pugh C, Kolaczkowski O, Manny A, Korithoski B, Kolaczkowski B. Resurrecting ancestral structural dynamics of an antiviral immune receptor: adaptive binding pocket reorganization repeatedly shifts RNA preference. BMC Evol Biol 2016; 16:241. [PMID: 27825296 PMCID: PMC5101713 DOI: 10.1186/s12862-016-0818-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 10/28/2016] [Indexed: 02/07/2023] Open
Abstract
Background Although resurrecting ancestral proteins is a powerful tool for understanding the molecular-functional evolution of gene families, nearly all studies have examined proteins functioning in relatively stable biological processes. The extent to which more dynamic systems obey the same ‘rules’ governing stable processes is unclear. Here we present the first detailed investigation of the functional evolution of the RIG-like receptors (RLRs), a family of innate immune receptors that detect viral RNA in the cytoplasm. Results Using kinetic binding assays and molecular dynamics simulations of ancestral proteins, we demonstrate how a small number of adaptive protein-coding changes repeatedly shifted the RNA preference of RLRs throughout animal evolution by reorganizing the shape and electrostatic distribution across the RNA binding pocket, altering the hydrogen bond network between the RLR and its RNA target. In contrast to observations of proteins involved in metabolism and development, we find that RLR-RNA preference ‘flip flopped’ between two functional states, and shifts in RNA preference were not always coupled to gene duplications or speciation events. We demonstrate at least one reversion of RLR-RNA preference from a derived to an ancestral function through a novel structural mechanism, indicating multiple structural implementations of similar functions. Conclusions Our results suggest a model in which frequent shifts in selection pressures imposed by an evolutionary arms race preclude the long-term functional optimization observed in stable biological systems. As a result, the evolutionary dynamics of immune receptors may be less constrained by structural epistasis and historical contingency. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0818-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Charles Pugh
- Department of Microbiology & Cell Science and Institute for Food and Agricultural Sciences, University of Florida, Gainesville, USA
| | - Oralia Kolaczkowski
- Department of Microbiology & Cell Science and Institute for Food and Agricultural Sciences, University of Florida, Gainesville, USA
| | - Austin Manny
- Department of Microbiology & Cell Science and Institute for Food and Agricultural Sciences, University of Florida, Gainesville, USA
| | - Bryan Korithoski
- Department of Microbiology & Cell Science and Institute for Food and Agricultural Sciences, University of Florida, Gainesville, USA
| | - Bryan Kolaczkowski
- Department of Microbiology & Cell Science and Institute for Food and Agricultural Sciences, University of Florida, Gainesville, USA. .,Genetics Institute, University of Florida, Gainesville, USA.
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9
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Two common structural motifs for TCR recognition by staphylococcal enterotoxins. Sci Rep 2016; 6:25796. [PMID: 27180909 PMCID: PMC4867771 DOI: 10.1038/srep25796] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 04/18/2016] [Indexed: 12/29/2022] Open
Abstract
Superantigens are toxins produced by Staphylococcus aureus, called staphylococcal enterotoxins (abbreviated SEA to SEU). They can cross-link the T cell receptor (TCR) and major histocompatibility complex class II, triggering a massive T cell activation and hence disease. Due to high stability and toxicity, superantigens are potential agents of bioterrorism. Hence, antagonists may not only be useful in the treatment of disease but also serve as countermeasures to biological warfare. Of particular interest are inhibitors against SEA and SEB. SEA is the main cause of food poisoning, while SEB is a common toxin manufactured as a biological weapon. Here, we present the crystal structures of SEA in complex with TCR and SEE in complex with the same TCR, complemented with computational alanine-scanning mutagenesis of SEA, SEB, SEC3, SEE, and SEH. We have identified two common areas that contribute to the general TCR binding for these superantigens. This paves the way for design of single antagonists directed towards multiple toxins.
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10
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Rosenfeld L, Heyne M, Shifman JM, Papo N. Protein Engineering by Combined Computational and In Vitro Evolution Approaches. Trends Biochem Sci 2016; 41:421-433. [PMID: 27061494 DOI: 10.1016/j.tibs.2016.03.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 02/29/2016] [Accepted: 03/09/2016] [Indexed: 12/30/2022]
Abstract
Two alternative strategies are commonly used to study protein-protein interactions (PPIs) and to engineer protein-based inhibitors. In one approach, binders are selected experimentally from combinatorial libraries of protein mutants that are displayed on a cell surface. In the other approach, computational modeling is used to explore an astronomically large number of protein sequences to select a small number of sequences for experimental testing. While both approaches have some limitations, their combination produces superior results in various protein engineering applications. Such applications include the design of novel binders and inhibitors, the enhancement of affinity and specificity, and the mapping of binding epitopes. The combination of these approaches also aids in the understanding of the specificity profiles of various PPIs.
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Affiliation(s)
- Lior Rosenfeld
- Department of Biotechnology Engineering and the National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Michael Heyne
- Department of Biotechnology Engineering and the National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Julia M Shifman
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Niv Papo
- Department of Biotechnology Engineering and the National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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11
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Importance of asparagine on the conformational stability and chemical reactivity of selected anti-inflammatory peptides. Chem Phys 2015. [DOI: 10.1016/j.chemphys.2015.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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12
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Rödström KEJ, Regenthal P, Lindkvist-Petersson K. Structure of Staphylococcal Enterotoxin E in Complex with TCR Defines the Role of TCR Loop Positioning in Superantigen Recognition. PLoS One 2015; 10:e0131988. [PMID: 26147596 PMCID: PMC4492778 DOI: 10.1371/journal.pone.0131988] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 06/09/2015] [Indexed: 11/18/2022] Open
Abstract
T cells are crucial players in cell-mediated immunity. The specificity of their receptor, the T cell receptor (TCR), is central for the immune system to distinguish foreign from host antigens. Superantigens are bacterial toxins capable of inducing a toxic immune response by cross-linking the TCR and the major histocompatibility complex (MHC) class II and circumventing the antigen specificity. Here, we present the structure of staphylococcal enterotoxin E (SEE) in complex with a human T cell receptor, as well as the unligated T cell receptor structure. There are clear structural changes in the TCR loops upon superantigen binding. In particular, the HV4 loop moves to circumvent steric clashes upon complex formation. In addition, a predicted ternary model of SEE in complex with both TCR and MHC class II displays intermolecular contacts between the TCR α-chain and the MHC, suggesting that the TCR α-chain is of importance for complex formation.
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Affiliation(s)
- Karin E. J. Rödström
- Department of Experimental Medical Science, Lund University, BMC C13, 22 184, Lund, Sweden
| | - Paulina Regenthal
- Department of Experimental Medical Science, Lund University, BMC C13, 22 184, Lund, Sweden
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13
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Sharma P, Wang N, Kranz DM. Soluble T cell receptor Vβ domains engineered for high-affinity binding to staphylococcal or streptococcal superantigens. Toxins (Basel) 2014; 6:556-74. [PMID: 24476714 PMCID: PMC3942751 DOI: 10.3390/toxins6020556] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 01/21/2014] [Accepted: 01/22/2014] [Indexed: 11/29/2022] Open
Abstract
Staphylococcus aureus and group A Streptococcus secrete a collection of toxins called superantigens (SAgs), so-called because they stimulate a large fraction of an individual’s T cells. One consequence of this hyperactivity is massive cytokine release leading to severe tissue inflammation and, in some cases, systemic organ failure and death. The molecular basis of action involves the binding of the SAg to both a T cell receptor (TCR) on a T cell and a class II product of the major histocompatibility complex (MHC) on an antigen presenting cell. This cross-linking leads to aggregation of the TCR complex and signaling. A common feature of SAgs is that they bind with relatively low affinity to the variable region (V) of the beta chain of the TCR. Despite this low affinity binding, SAgs are very potent, as each T cell requires only a small fraction of their receptors to be bound in order to trigger cytokine release. To develop high-affinity agents that could neutralize the activity of SAgs, and facilitate the development of detection assays, soluble forms of the Vβ regions have been engineered to affinities that are up to 3 million-fold higher for the SAg. Over the past decade, six different Vβ regions against SAgs from S. aureus (SEA, SEB, SEC3, TSST-1) or S. pyogenes (SpeA and SpeC) have been engineered for high-affinity using yeast display and directed evolution. Here we review the engineering of these high-affinity Vβ proteins, structural features of the six different SAgs and the Vβ proteins, and the specific properties of the engineered Vβ regions that confer high-affinity and specificity for their SAg ligands.
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Affiliation(s)
- Preeti Sharma
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA.
| | - Ningyan Wang
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA.
| | - David M Kranz
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA.
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14
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Mattis D, Spaulding A, Chuang-Smith O, Sundberg E, Schlievert P, Kranz D. Engineering a soluble high-affinity receptor domain that neutralizes staphylococcal enterotoxin C in rabbit models of disease. Protein Eng Des Sel 2013; 26:133-42. [PMID: 23161916 PMCID: PMC3542526 DOI: 10.1093/protein/gzs094] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 08/31/2012] [Accepted: 10/17/2012] [Indexed: 11/13/2022] Open
Abstract
Superantigens (SAgs) are a class of immunostimulatory exotoxins that activate large numbers of T cells, leading to overproduction of cytokines and subsequent inflammatory reactions and systemic toxicity. Staphylococcal enterotoxin C (SEC), a SAg secreted by Staphylococcus aureus, has been implicated in various illnesses including non-menstrual toxic shock syndrome (TSS) and necrotizing pneumonia. SEC has been shown to cause TSS illness in rabbits and the toxin contributes to lethality associated with methicillin-resistant S.aureus (MRSA) in a rabbit model of pneumonia. With the goal of reducing morbidity and mortality associated with SEC, a high-affinity variant of the extracellular variable domain of the T-cell receptor beta-chain for SEC (~14 kDa) was generated by directed evolution using yeast display. This protein was characterized biochemically and shown to cross-react with the homologous (65% identical) SAg staphylococcal enterotoxin B (SEB). The soluble, high-affinity T-cell receptor protein neutralized SEC and SEB in vitro and also significantly reduced the bacterial burden of an SEC-positive strain of MRSA (USA400 MW2) in an infective endocarditis model. The neutralizing agent also prevented lethality due to MW2 in a necrotizing pneumonia rabbit model. These studies characterize a soluble high-affinity neutralizing agent against SEC, which is cross-reactive with SEB, and that has potential to be used intravenously with antibiotics to manage staphylococcal diseases that involve these SAgs.
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MESH Headings
- Animals
- Anti-Bacterial Agents/administration & dosage
- Anti-Bacterial Agents/biosynthesis
- Anti-Bacterial Agents/chemistry
- Cell Line
- Cell Surface Display Techniques
- Directed Molecular Evolution
- Disease Models, Animal
- Endocarditis, Bacterial/drug therapy
- Endocarditis, Bacterial/immunology
- Endocarditis, Bacterial/microbiology
- Enterotoxins/antagonists & inhibitors
- Enterotoxins/metabolism
- Humans
- Interleukin-2/metabolism
- Lymphocyte Activation
- Methicillin-Resistant Staphylococcus aureus/immunology
- Methicillin-Resistant Staphylococcus aureus/metabolism
- Pneumonia, Staphylococcal/drug therapy
- Pneumonia, Staphylococcal/immunology
- Pneumonia, Staphylococcal/microbiology
- Protein Binding
- Protein Engineering
- Rabbits
- Receptors, Antigen, T-Cell, alpha-beta/administration & dosage
- Receptors, Antigen, T-Cell, alpha-beta/biosynthesis
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Recombinant Proteins/administration & dosage
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Staphylococcal Infections/drug therapy
- Staphylococcal Infections/immunology
- Staphylococcal Infections/microbiology
- Superantigens/metabolism
- Superantigens/pharmacology
- T-Lymphocytes/drug effects
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
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Affiliation(s)
- D.M. Mattis
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - A.R. Spaulding
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
- Present address: Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA
| | - O.N. Chuang-Smith
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - E.J. Sundberg
- Boston Biomedical Research Institute, Watertown, MA 02472, USA
- Present address: Institute of Human Virology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - P.M. Schlievert
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
- Present address: Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA
| | - D.M. Kranz
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
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15
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Han J, Kim HJ, Lee SC, Hong S, Park K, Jeon YH, Kim D, Cheong HK, Kim HS. Structure-based rational design of a Toll-like receptor 4 (TLR4) decoy receptor with high binding affinity for a target protein. PLoS One 2012; 7:e30929. [PMID: 22363519 PMCID: PMC3281905 DOI: 10.1371/journal.pone.0030929] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 12/27/2011] [Indexed: 11/18/2022] Open
Abstract
Repeat proteins are increasingly attracting much attention as alternative scaffolds to immunoglobulin antibodies due to their unique structural features. Nonetheless, engineering interaction interface and understanding molecular basis for affinity maturation of repeat proteins still remain a challenge. Here, we present a structure-based rational design of a repeat protein with high binding affinity for a target protein. As a model repeat protein, a Toll-like receptor4 (TLR4) decoy receptor composed of leucine-rich repeat (LRR) modules was used, and its interaction interface was rationally engineered to increase the binding affinity for myeloid differentiation protein 2 (MD2). Based on the complex crystal structure of the decoy receptor with MD2, we first designed single amino acid substitutions in the decoy receptor, and obtained three variants showing a binding affinity (K(D)) one-order of magnitude higher than the wild-type decoy receptor. The interacting modes and contributions of individual residues were elucidated by analyzing the crystal structures of the single variants. To further increase the binding affinity, single positive mutations were combined, and two double mutants were shown to have about 3000- and 565-fold higher binding affinities than the wild-type decoy receptor. Molecular dynamics simulations and energetic analysis indicate that an additive effect by two mutations occurring at nearby modules was the major contributor to the remarkable increase in the binding affinities.
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Affiliation(s)
- Jieun Han
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, Korea
| | - Hyun Jung Kim
- Division of Magnetic Resonance Research, Korea Basic Science Institute, Cheongwon, Chungbuk, Korea
- College of Pharmacy, Chungbuk National University, Cheongju, Chungbuk, Korea
| | - Sang-Chul Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, Korea
| | - Seungpyo Hong
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, Korea
| | - Keunwan Park
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, Korea
| | - Young Ho Jeon
- Division of Magnetic Resonance Research, Korea Basic Science Institute, Cheongwon, Chungbuk, Korea
| | - Dongsup Kim
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, Korea
| | - Hae-Kap Cheong
- Division of Magnetic Resonance Research, Korea Basic Science Institute, Cheongwon, Chungbuk, Korea
- * E-mail: (H-KC); (H-SK)
| | - Hak-Sung Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, Korea
- Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, Korea
- * E-mail: (H-KC); (H-SK)
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16
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17
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Zhou B, Chen Q, Mallis RJ, Zhang H, Liu JH, Reinherz EL, Wang JH. A conserved hydrophobic patch on Vβ domains revealed by TCRβ chain crystal structures: Implications for pre-TCR dimerization. Front Immunol 2011; 2:5. [PMID: 22566796 PMCID: PMC3341985 DOI: 10.3389/fimmu.2011.00005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 02/15/2011] [Indexed: 01/21/2023] Open
Abstract
The αβ T cell receptor (TCR) is a multimeric complex whose β chain plays a crucial role in thymocyte development as well as antigen recognition by mature T lymphocytes. We report here crystal structures of individual β subunits, termed N15β (Vβ5.2Dβ2Jβ2.6Cβ2) and N30β (Vβ13Dβ1Jβ1.1Cβ2), derived from two αβ TCRs specific for the immunodominant vesicular stomatitis virus octapeptide (VSV-8) bound to the murine H-2Kb MHC class I molecule. The crystal packing of the N15β structure reveals a homodimer formed through two Vβ domains. The Vβ/Vβ module is topologically very similar to the Vα/Vβ module in the N15αβ heterodimer. By contrast, in the N30β structure, the Vβ domain’s external hydrophobic CFG face is covered by the neighboring molecule’s Cβ domain. In conjunction with systematic investigation of previously published TCR single-subunit structures, we identified several conserved residues forming a concave hydrophobic patch at the center of the CFG outer face of the Vβ and other V-type Ig-like domains. This hydrophobic patch is shielded from solvent exposure in the crystal packing, implying that it is unlikely to be thermodynamically stable if exposed on the thymocyte surface. Accordingly, we propose a dimeric pre-TCR model distinct from those suggested previously by others and discuss its functional and structural implications.
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Affiliation(s)
- Bo Zhou
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Harvard Medical School Boston, MA, USA
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18
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Bonsor DA, Sundberg EJ. Dissecting protein-protein interactions using directed evolution. Biochemistry 2011; 50:2394-402. [PMID: 21332192 DOI: 10.1021/bi102019c] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protein-protein interactions are essential for life. They are responsible for most cellular functions and when they go awry often lead to disease. Proteins are inherently complex. They are flexible macromolecules whose constituent amino acid components act in combinatorial and networked ways when they engage one another in binding interactions. It is just this complexity that allows them to conduct such a broad array of biological functions. Despite decades of intense study of the molecular basis of protein-protein interactions, key gaps in our understanding remain, hindering our ability to accurately predict the specificities and affinities of their interactions. Until recently, most protein-protein investigations have been probed experimentally at the single-amino acid level, making them, by definition, incapable of capturing the combinatorial nature of, and networked communications between, the numerous residues within and outside of the protein-protein interface. This aspect of protein-protein interactions, however, is emerging as a major driving force for protein affinity and specificity. Understanding a combinatorial process necessarily requires a combinatorial experimental tool. Much like the organisms in which they reside, proteins naturally evolve over time, through a combinatorial process of mutagenesis and selection, to functionally associate. Elucidating the process by which proteins have evolved may be one of the keys to deciphering the molecular rules that govern their interactions with one another. Directed evolution is a technique performed in the laboratory that mimics natural evolution on a tractable time scale that has been utilized widely to engineer proteins with novel capabilities, including altered binding properties. In this review, we discuss directed evolution as an emerging tool for dissecting protein-protein interactions.
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Affiliation(s)
- Daniel A Bonsor
- Boston Biomedical Research Institute, 64 Grove Street, Watertown, Massachusetts 02472, United States
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19
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Fernández MM, Cho S, De Marzi MC, Kerzic MC, Robinson H, Mariuzza RA, Malchiodi EL. Crystal structure of staphylococcal enterotoxin G (SEG) in complex with a mouse T-cell receptor {beta} chain. J Biol Chem 2011; 286:1189-95. [PMID: 21059660 PMCID: PMC3020726 DOI: 10.1074/jbc.m110.142471] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 09/20/2010] [Indexed: 11/06/2022] Open
Abstract
Superantigens (SAgs) are bacterial or viral toxins that bind MHC class II (MHC-II) molecules and T-cell receptor (TCR) in a nonconventional manner, inducing T-cell activation that leads to inflammatory cytokine production, which may result in acute toxic shock. In addition, the emerging threat of purpura fulminans and community-associated meticillin-resistant Staphylococcus aureus emphasizes the importance of a better characterization of SAg binding to their natural ligands that may allow the development of reagents to neutralize their action. The three-dimensional structure of the complex between a mouse TCR β chain (mVβ8.2) and staphylococcal enterotoxin G (SEG) at 2.0 Å resolution revealed a binding site that does not conserve the "hot spots" present in mVβ8.2-SEC2, mVβ8.2-SEC3, mVβ8.2-SEB, and mVβ8.2-SPEA complexes. Analysis of the mVβ8.2-SEG interface allowed us to explain the higher affinity of this complex compared with the others, which may account for the early activation of T-cells bearing mVβ8.2 by SEG. This mode of interaction between SEG and mVβ8.2 could be an adaptive advantage to bestow on the pathogen a faster rate of colonization of the host.
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Affiliation(s)
- Marisa M. Fernández
- From the Cátedra de Inmunología and Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956 4to P, 1113 Buenos Aires, Argentina
- the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
| | - Sangwoo Cho
- the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
| | - Mauricio C. De Marzi
- From the Cátedra de Inmunología and Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956 4to P, 1113 Buenos Aires, Argentina
- Departamento de Ciencias Básicas, Universidad Nacional de Luján, Ruta 5 y Constitución, 6700 Luján, Buenos Aires, Argentina, and
| | - Melissa C. Kerzic
- the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
| | - Howard Robinson
- Department of Biology, Brookhaven National Laboratory, Upton, New York 11973
| | - Roy A. Mariuzza
- the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
| | - Emilio L. Malchiodi
- From the Cátedra de Inmunología and Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956 4to P, 1113 Buenos Aires, Argentina
- the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
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20
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Cho S, Swaminathan CP, Bonsor DA, Kerzic MC, Guan R, Yang J, Kieke MC, Andersen PS, Kranz DM, Mariuzza RA, Sundberg EJ. Assessing energetic contributions to binding from a disordered region in a protein-protein interaction . Biochemistry 2010; 49:9256-68. [PMID: 20836565 DOI: 10.1021/bi1008968] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Many functional proteins are at least partially disordered prior to binding. Although the structural transitions upon binding of disordered protein regions can influence the affinity and specificity of protein complexes, their precise energetic contributions to binding are unknown. Here, we use a model protein-protein interaction system in which a locally disordered region has been modified by directed evolution to quantitatively assess the thermodynamic and structural contributions to binding of disorder-to-order transitions. Through X-ray structure determination of the protein binding partners before and after complex formation and isothermal titration calorimetry of the interactions, we observe a correlation between protein ordering and binding affinity for complexes along this affinity maturation pathway. Additionally, we show that discrepancies between observed and calculated heat capacities based on buried surface area changes in the protein complexes can be explained largely by heat capacity changes that would result solely from folding the locally disordered region. Previously developed algorithms for predicting binding energies of protein-protein interactions, however, are unable to correctly model the energetic contributions of the structural transitions in our model system. While this highlights the shortcomings of current computational methods in modeling conformational flexibility, it suggests that the experimental methods used here could provide training sets of molecular interactions for improving these algorithms and further rationalizing molecular recognition in protein-protein interactions.
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Affiliation(s)
- Sangwoo Cho
- W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA
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21
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Haidar JN, Pierce B, Yu Y, Tong W, Li M, Weng Z. Structure-based design of a T-cell receptor leads to nearly 100-fold improvement in binding affinity for pepMHC. Proteins 2009; 74:948-60. [PMID: 18767161 DOI: 10.1002/prot.22203] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
T-cell receptors (TCRs) are proteins that recognize peptides from foreign proteins bound to the major histocompatibility complex (MHC) on the surface of an antigen-presenting cell. This interaction enables the T cells to initiate a cell-mediated immune response to terminate cells displaying the foreign peptide on their MHC. Naturally occurring TCRs have high specificity but low affinity toward the peptide-MHC (pepMHC) complex. This prevents the usage of solubilized TCRs for diagnosis and treatment of viral infections or cancers. Efforts to enhance the binding affinity of several TCRs have been reported in recent years, through randomized libraries and in vitro selection. However, there have been no reported efforts to enhance the affinity via structure-based design, which allows more control and understanding of the mechanism of improvement. Here, we have applied structure-based design to a human TCR to improve its pepMHC binding. Our design method evolved based on iterative steps of prediction, testing, and generating more predictions based on the new data. The final design function, named ZAFFI, has a correlation of 0.77 and average error of 0.35 kcal/mol with the binding free energies of 26 point mutations for this system that we measured by surface plasmon resonance (SPR). Applying the filter that we developed to remove nonbinding predictions, this correlation increases to 0.85, and the average error decreases to 0.3 kcal/mol. Using this algorithm, we predicted and tested several point mutations that improved binding, with one giving over sixfold binding improvement. Four of the point mutations that improved binding were then combined to give a mutant TCR that binds the pepMHC 99 times more strongly than the wild-type TCR.
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Affiliation(s)
- Jaafar N Haidar
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
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22
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Wong S, Amaro RE, McCammon JA. MM-PBSA Captures Key Role of Intercalating Water Molecules at a Protein-Protein Interface. J Chem Theory Comput 2009; 5:422-429. [PMID: 19461869 PMCID: PMC2651627 DOI: 10.1021/ct8003707] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Indexed: 11/28/2022]
Abstract
The calculation of protein interaction energetics is of fundamental interest, yet accurate quantities are difficult to obtain due to the complex and dynamic nature of protein interfaces. This is further complicated by the presence of water molecules, which can exhibit transient interactions of variable duration and strength with the protein surface. The T-cell receptor (TCR) and its staphylococcal enterotoxin 3 (SEC3) binding partner are well-characterized examples of a protein−protein interaction system exhibiting interfacial plasticity, cooperativity, and additivity among mutants. Specifically engineered mutants induce intercalating interfacial water molecules, which subsequently enhance protein−protein binding affinity. In this work, we perform a set of molecular mechanics (MM) Poisson−Boltzmann (PB) surface area (SA) calculations on the wild type and two mutant TCR-SEC3 systems and show that the method is able to discriminate between weak and strong binders only when key explicit water molecules are included in the analysis. The results presented here point to the promise of MM-PBSA toward rationalizing molecular recognition at protein−protein interfaces, while establishing a general approach to handle explicit interfacial water molecules in such calculations.
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Affiliation(s)
- Sergio Wong
- Department of Chemistry and Biochemistry, Center for Theoretical Biological Physics, Department of Pharmacology, and Howard Hughes Medical Institute, University of California at San Diego, La Jolla, California 92093-0365
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23
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Kasper KJ, Xi W, Rahman AKMNU, Nooh MM, Kotb M, Sundberg EJ, Madrenas J, McCormick JK. Molecular requirements for MHC class II alpha-chain engagement and allelic discrimination by the bacterial superantigen streptococcal pyrogenic exotoxin C. THE JOURNAL OF IMMUNOLOGY 2008; 181:3384-92. [PMID: 18714010 DOI: 10.4049/jimmunol.181.5.3384] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Superantigens (SAgs) are microbial toxins that bind to both TCR beta-chain variable domains (Vbetas) and MHC class II molecules, resulting in the activation of T cells in a Vbeta-specific manner. It is now well established that different isoforms of MHC II molecules can play a significant role in the immune response to bacterial SAgs. In this work, using directed mutational studies in conjunction with functional analyses, we provide a complete functional map of the low-affinity MHC II alpha-chain binding interface of the SAg streptococcal pyrogenic exotoxin C (SpeC) and identify a functional epitope in the beta-barrel domain that is required for the activation of T cells. Using cell lines that exclusively express individual MHC II isoforms, our studies provide a molecular basis for the selectivity of SpeC-MHC II recognition, and provide one mechanism by how SAgs are capable of distinguishing between different MHC II alleles.
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Affiliation(s)
- Katherine J Kasper
- Department of Microbiology and Immunology, University of Western Ontario, Canada
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24
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Tummino PJ, Copeland RA. Residence time of receptor-ligand complexes and its effect on biological function. Biochemistry 2008; 47:5481-92. [PMID: 18412369 DOI: 10.1021/bi8002023] [Citation(s) in RCA: 392] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The formation and duration of binary receptor-ligand complexes are fundamental to many physiologic processes. Most often, the effectiveness of interaction between a receptor and its ligand is quantified in terms of closed system, equilibrium affinity measurements, such as IC50 and Kd. In the context of in vivo biology, however, the extent and duration of responses to receptor-ligand interactions depend greatly on the time period over which the ligand is in residence on its receptor. Here we define receptor-ligand complex residence time in quantitative terms and describe its significance to biological function. Examples of the importance of residence time are presented for natural ligands of different receptor types. The impact of residence time on the optimization of potential ligands as drugs for human medicine is also described.
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Affiliation(s)
- Peter J Tummino
- Department of Enzymology and Mechanistic Pharmacology and Department of Oncology Biology, Oncology Center of Excellence in Drug Discovery, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426, USA.
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25
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Keskin O, Gursoy A, Ma B, Nussinov R. Principles of Protein−Protein Interactions: What are the Preferred Ways For Proteins To Interact? Chem Rev 2008; 108:1225-44. [DOI: 10.1021/cr040409x] [Citation(s) in RCA: 476] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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Matthews MM, Weber DJ, Shapiro PS, Coop A, Mackerell AD. Inhibition of protein-protein interactions with low molecular weight compounds. CURRENT TRENDS IN MEDICINAL CHEMISTRY 2008; 5:21-32. [PMID: 21927717 PMCID: PMC3173769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
An overview of issues associated with the design and development of low molecular weight inhibitors of protein-protein interactions is presented. Areas discussed include information on the nature of protein-protein interfaces, methods to characterize those interfaces and methods by which that information is applied towards ligand identification and design. Specific examples of the strategy for the identification of inhibitors of protein-protein interactions involving the proteins p56lck kinase, ERK2 and the calcium-binding protein S100B are presented. Physical characterization of the inhibitors identified in those studies shows them to have drug-like and lead-like properties, indicating their potential to be developed into therapeutic agents.
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Affiliation(s)
- Marilyn M Matthews
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, 20 Penn Street, Baltimore, MD, 21201
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27
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Koide A, Tereshko V, Uysal S, Margalef K, Kossiakoff AA, Koide S. Exploring the capacity of minimalist protein interfaces: interface energetics and affinity maturation to picomolar KD of a single-domain antibody with a flat paratope. J Mol Biol 2007; 373:941-53. [PMID: 17888451 PMCID: PMC2148503 DOI: 10.1016/j.jmb.2007.08.027] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Revised: 08/09/2007] [Accepted: 08/11/2007] [Indexed: 11/29/2022]
Abstract
A major architectural class in engineered binding proteins ("antibody mimics") involves the presentation of recognition loops off a single-domain scaffold. This class of binding proteins, both natural and synthetic, has a strong tendency to bind a preformed cleft using a convex binding interface (paratope). To explore their capacity to produce high-affinity interfaces with diverse shape and topography, we examined the interface energetics and explored the affinity limit achievable with a flat paratope. We chose a minimalist paratope limited to two loops found in a natural camelid heavy-chain antibody (VHH) that binds to ribonuclease A. Ala scanning of the VHH revealed only three "hot spot" side chains and additional four residues important for supporting backbone-mediated interactions. The small number of critical residues suggested that this is not an optimized paratope. Using selection from synthetic combinatorial libraries, we enhanced its affinity by >100-fold, resulting in variants with Kd as low as 180 pM with no detectable loss of binding specificity. High-resolution crystal structures revealed that the mutations induced only subtle structural changes but extended the network of interactions. This resulted in an expanded hot spot region including four additional residues located at the periphery of the paratope with a concomitant loss of the so-called "O-ring" arrangement of energetically inert residues. These results suggest that this class of simple, single-domain scaffolds is capable of generating high-performance binding interfaces with diverse shape. More generally, they suggest that highly functional interfaces can be designed without closely mimicking natural interfaces.
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Affiliation(s)
| | | | | | | | | | - Shohei Koide
- To whom correspondence should be addressed: email, ; FAX, 1-773-702-0439
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28
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Fernández MM, Bhattacharya S, De Marzi MC, Brown PH, Kerzic M, Schuck P, Mariuzza RA, Malchiodi EL. Superantigen natural affinity maturation revealed by the crystal structure of staphylococcal enterotoxin G and its binding to T-cell receptor Vβ8.2. Proteins 2007; 68:389-402. [PMID: 17427250 DOI: 10.1002/prot.21388] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The illnesses associated with bacterial superantigens (SAgs) such as food poisoning and toxic shock syndrome, as well as the emerging threat of purpura fulminans and community-associated methicillin-resistant S. aureus producer of SAgs, emphasize the importance of a better characterization of SAg binding to their natural ligands, which would allow the development of drugs or biological reagents able to neutralize their action. SAgs are toxins that bind major histocompatibility complex class II molecules (MHC-II) and T-cell receptors (TCR), in a nonconventional manner, inducing T-cell activation that leads to production of cytokines such as tumor necrosis factor and interleukin-2, which may result in acute toxic shock. Previously, we cloned and expressed a new natural variant of staphylococcal enterotoxin G (SEG) and evaluated its ability to stimulate in vivo murine T-cell subpopulations. We found an early, strong, and widespread stimulation of mouse Vbeta8.2 T-cells when compared with other SAgs member of the SEB subfamily. In search for the reason of the strong mitogenic potency, we determined the SEG crystal structure by X-ray crystallography to 2.2 A resolution and analyzed SEG binding to mVbeta8.2 and MHC-II. Calorimetry and SPR analysis showed that SEG has an affinity for mVbeta8.2 40 to 100-fold higher than that reported for other members of SEB subfamily, and the highest reported for a wild type SAg-TCR couple. We also found that mutations introduced in mVbeta8.2 to produce a high affinity mutant for other members of the SEB subfamily do not greatly affect binding to SEG. Crystallographic analysis and docking into mVbeta8.2 in complex with SEB, SEC3, and SPEA showed that the deletions and substitution of key amino acids remodeled the putative surface of the mVbeta8.2 binding site without affecting the binding to MHC-II. This results in a SAg with improved binding to its natural ligands, which may confer a possible evolutionary advantage for bacterial strains expressing SEG.
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Affiliation(s)
- Marisa M Fernández
- Instituto de Estudios de la Inmunidad Humoral, Laboratorio de Inmunología Estructural, CONICET, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
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29
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Moza B, Varma AK, Buonpane RA, Zhu P, Herfst CA, Nicholson MJ, Wilbuer AK, Seth NP, Wucherpfennig KW, McCormick JK, Kranz DM, Sundberg EJ. Structural basis of T-cell specificity and activation by the bacterial superantigen TSST-1. EMBO J 2007; 26:1187-97. [PMID: 17268555 PMCID: PMC1852840 DOI: 10.1038/sj.emboj.7601531] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2006] [Accepted: 12/07/2006] [Indexed: 01/12/2023] Open
Abstract
Superantigens (SAGs) bind simultaneously to major histocompatibility complex (MHC) and T-cell receptor (TCR) molecules, resulting in the massive release of inflammatory cytokines that can lead to toxic shock syndrome (TSS) and death. A major causative agent of TSS is toxic shock syndrome toxin-1 (TSST-1), which is unique relative to other bacterial SAGs owing to its structural divergence and its stringent TCR specificity. Here, we report the crystal structure of TSST-1 in complex with an affinity-matured variant of its wild-type TCR ligand, human T-cell receptor beta chain variable domain 2.1. From this structure and a model of the wild-type complex, we show that TSST-1 engages TCR ligands in a markedly different way than do other SAGs. We provide a structural basis for the high TCR specificity of TSST-1 and present a model of the TSST-1-dependent MHC-SAG-TCR T-cell signaling complex that is structurally and energetically unique relative to those formed by other SAGs. Our data also suggest that protein plasticity plays an exceptionally significant role in this affinity maturation process that results in more than a 3000-fold increase in affinity.
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Affiliation(s)
- Beenu Moza
- Boston Biomedical Research Institute, Watertown, MA, USA
| | - Ashok K Varma
- Boston Biomedical Research Institute, Watertown, MA, USA
| | | | - Penny Zhu
- Boston Biomedical Research Institute, Watertown, MA, USA
| | - Christine A Herfst
- Department of Microbiology and Immunology, Lawson Health Research Institute, University of Western Ontario, London, Ontario, Canada
| | - Melissa J Nicholson
- Department of Cancer Immunology and AIDS, Dana Farber Cancer Research Institute, Harvard Medical School, Boston, MA, USA
| | - Anne-Kathrin Wilbuer
- Department of Cancer Immunology and AIDS, Dana Farber Cancer Research Institute, Harvard Medical School, Boston, MA, USA
- Program in Immunology, Harvard Medical School, Boston, MA, USA
| | - Nilufer P Seth
- Department of Cancer Immunology and AIDS, Dana Farber Cancer Research Institute, Harvard Medical School, Boston, MA, USA
| | - Kai W Wucherpfennig
- Department of Cancer Immunology and AIDS, Dana Farber Cancer Research Institute, Harvard Medical School, Boston, MA, USA
- Program in Immunology, Harvard Medical School, Boston, MA, USA
- Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - John K McCormick
- Department of Microbiology and Immunology, Lawson Health Research Institute, University of Western Ontario, London, Ontario, Canada
| | - David M Kranz
- Department of Biochemistry, University of Illinois, Urbana, IL, USA
| | - Eric J Sundberg
- Boston Biomedical Research Institute, Watertown, MA, USA
- Boston Biomedical Research Institute, 64 Grove Street, Watertown, MA 02472, USA. Tel.: +1 617 658 7882; Fax: +1 617 972 1761; E-mail:
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Reichmann D, Rahat O, Cohen M, Neuvirth H, Schreiber G. The molecular architecture of protein-protein binding sites. Curr Opin Struct Biol 2007; 17:67-76. [PMID: 17239579 DOI: 10.1016/j.sbi.2007.01.004] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2006] [Revised: 12/13/2006] [Accepted: 01/10/2007] [Indexed: 11/16/2022]
Abstract
The formation of specific protein interactions plays a crucial role in most, if not all, biological processes, including signal transduction, cell regulation, the immune response and others. Recent advances in our understanding of the molecular architecture of protein-protein binding sites, which facilitates such diversity in binding affinity and specificity, are enabling us to address key questions. What is the amino acid composition of binding sites? What are interface hotspots? How are binding sites organized? What are the differences between tight and weak interacting complexes? How does water contribute to binding? Can the knowledge gained be translated into protein design? And does a universal code for binding exist, or is it the architecture and chemistry of the interface that enable diverse but specific binding solutions?
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Affiliation(s)
- Dana Reichmann
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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Rahman AKMNU, Herfst CA, Moza B, Shames SR, Chau LA, Bueno C, Madrenas J, Sundberg EJ, McCormick JK. Molecular Basis of TCR Selectivity, Cross-Reactivity, and Allelic Discrimination by a Bacterial Superantigen: Integrative Functional and Energetic Mapping of the SpeC-Vβ2.1 Molecular Interface. THE JOURNAL OF IMMUNOLOGY 2006; 177:8595-603. [PMID: 17142758 DOI: 10.4049/jimmunol.177.12.8595] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Superantigens activate large fractions of T cells through unconventional interactions with both TCR beta-chain V domains (Vbetas) and MHC class II molecules. The bacterial superantigen streptococcal pyrogenic exotoxin C (SpeC) primarily stimulates human Vbeta2(+) T cells. Herein, we have analyzed the SpeC-Vbeta2.1 interaction by mutating all SpeC residues that make contact with Vbeta2.1 and have determined the energetic and functional consequences of these mutations. Our comprehensive approach, including mutagenesis, functional readouts from both bulk T cell populations, and an engineered Vbeta2.1(+) Jurkat T cell, as well as surface plasmon resonance binding analysis, has defined the SpeC "functional epitope" for TCR engagement. Although only two SpeC residues (Tyr(15) and Arg(181)) are critical for activation of virtually all human CD3(+) T cells, a larger cluster of four hot spot residues are required for interaction with Vbeta2.1. Three of these residues (Tyr(15), Phe(75), and Arg(181)) concentrate their binding energy on the CDR2 loop residue Ser(52a), a noncanonical residue insertion found only in Vbeta2 and Vbeta4 chains. Plasticity of this loop is important for recognition by SpeC. Although SpeC interacts with the Vbeta2.1 hypervariable CDR3 loop, our data indicate these contacts have little to no influence on the functional interaction with Vbeta2.1. These studies also provide a molecular basis for selectivity and cross-reactivity of SpeC-TCR recognition and reveal a degree of fine specificity in these interactions, whereby certain SpeC mutants are capable of distinguishing between different alleles of the same Vbeta domain subfamily.
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Fernández MM, Guan R, Swaminathan CP, Malchiodi EL, Mariuzza RA. Crystal structure of staphylococcal enterotoxin I (SEI) in complex with a human major histocompatibility complex class II molecule. J Biol Chem 2006; 281:25356-64. [PMID: 16829512 PMCID: PMC2730046 DOI: 10.1074/jbc.m603969200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Superantigens are bacterial or viral proteins that elicit massive T cell activation through simultaneous binding to major histocompatibility complex (MHC) class II and T cell receptors. This activation results in uncontrolled release of inflammatory cytokines, causing toxic shock. A remarkable property of superantigens, which distinguishes them from T cell receptors, is their ability to interact with multiple MHC class II alleles independently of MHC-bound peptide. Previous crystallographic studies have shown that staphylococcal and streptococcal superantigens belonging to the zinc family bind to a high affinity site on the class II beta-chain. However, the basis for promiscuous MHC recognition by zinc-dependent superantigens is not obvious, because the beta-chain is polymorphic and the MHC-bound peptide forms part of the binding interface. To understand how zinc-dependent superantigens recognize MHC, we determined the crystal structure, at 2.0 A resolution, of staphylococcal enterotoxin I bound to the human class II molecule HLA-DR1 bearing a peptide from influenza hemagglutinin. Interactions between the superantigen and DR1 beta-chain are mediated by a zinc ion, and 22% of the buried surface of peptide.MHC is contributed by the peptide. Comparison of the staphylococcal enterotoxin I.peptide.DR1 structure with ones determined previously revealed that zinc-dependent superantigens achieve promiscuous binding to MHC by targeting conservatively substituted residues of the polymorphic beta-chain. Additionally, these superantigens circumvent peptide specificity by engaging MHC-bound peptides at their conformationally conserved N-terminal regions while minimizing sequence-specific interactions with peptide residues to enhance cross-reactivity.
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Affiliation(s)
- Marisa M Fernández
- Instituto de Estudios de la Inmunidad Humoral, Laboratorio de Inmunología Estructural, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
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