1
|
Mariuzza RA, Shahid S, Karade SS. The immune checkpoint receptor LAG3: Structure, function, and target for cancer immunotherapy. J Biol Chem 2024; 300:107241. [PMID: 38556085 PMCID: PMC11061240 DOI: 10.1016/j.jbc.2024.107241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 04/02/2024] Open
Abstract
Lymphocyte activation gene 3 protein (LAG3) is an immune checkpoint receptor that is highly upregulated on exhausted T cells in the tumor microenvironment. LAG3 transmits inhibitory signals to T cells upon binding to MHC class II and other ligands, rendering T cells dysfunctional. Consequently, LAG3 is a major target for cancer immunotherapy with many anti-LAG3 monoclonal antibodies (mAbs) that block LAG3 inhibitory activity in clinical trials. In this review, we examine the molecular basis for LAG3 function in light of recently determined crystal and cryoEM structures of this inhibitory receptor. We review what is known about LAG3 interactions with MHC class II, its canonical ligand, and the newly discovered ligands FGL1 and the T cell receptor (TCR)-CD3 complex, including current controversies over the relative importance of these ligands. We then address the development and mechanisms of action of anti-LAG3 mAbs in clinical trials for cancer immunotherapy. We discuss new strategies to therapeutically target LAG3 using mAbs that not only block the LAG3-MHC class II interaction, but also LAG3 interactions with FGL1 or TCR-CD3, or that disrupt LAG3 dimerization. Finally, we assess the possibility of developing mAbs that enhance, rather than block, LAG3 inhibitory activity as treatments for autoimmune diseases.
Collapse
Affiliation(s)
- Roy A Mariuzza
- W.M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland, USA; Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA.
| | - Salman Shahid
- W.M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland, USA; Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA
| | - Sharanbasappa S Karade
- W.M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland, USA; Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA
| |
Collapse
|
2
|
Bandyopadhyay A, Biswas P, Kundu SK, Sarkar R. Electrochemistry-enabled residue-specific modification of peptides and proteins. Org Biomol Chem 2024; 22:1085-1101. [PMID: 38231504 DOI: 10.1039/d3ob01857a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Selective chemical reactions at precise amino acid residues of peptides and proteins have become an exploding field of research in the last few decades. With the emerging utility of bioconjugated peptides and proteins as drug leads and therapeutic agents, the design of smart protocols to modulate and conjugate biomolecules has become necessary. During this modification, the most important concern of biochemists is to keep intact the structural integrity of the biomolecules. Hence, a soft and selective biocompatible reaction environment is necessary. Electrochemistry, a mild and elegant tunable reaction platform to synthesize complex molecules while avoiding harsh and toxic chemicals, can provide such a reaction condition. However, this strategy is yet to be fully exploited in the field of selective modification of polypeptides. With this possibility, the use of electrochemistry as a reaction toolbox in peptide and protein chemistry is flourishing day by day. Unfortunately, there is no suitable review article summarizing the residue-specific modification of biomolecules. The present review provides a comprehensive summary of the latest manifested electrochemical approaches for the modulation of five redox-active amino acid residues, namely cysteine, tyrosine, tryptophan, histidine and methionine, found in peptides and proteins. The article also highlights the incredible potential of electrochemistry for the regio- as well as chemoselective bioconjugation strategy of biomolecules.
Collapse
Affiliation(s)
- Ayan Bandyopadhyay
- Department of Chemistry, Chapra Government College, Nadia-741123, West Bengal, India
| | - Pranay Biswas
- Department of Physics, Dinabandhu Mahavidyalaya, 24 Parganas (N), 743235, West Bengal, India
| | - Sudipta K Kundu
- Department of Chemistry, Muragachha Government College, Nadia-741154, West Bengal, India.
| | - Rajib Sarkar
- Department of Chemistry, Muragachha Government College, Nadia-741154, West Bengal, India.
| |
Collapse
|
3
|
McShan AC, Flores-Solis D, Sun Y, Garfinkle SE, Toor JS, Young MC, Sgourakis NG. Conformational plasticity of RAS Q61 family of neoepitopes results in distinct features for targeted recognition. Nat Commun 2023; 14:8204. [PMID: 38081856 PMCID: PMC10713829 DOI: 10.1038/s41467-023-43654-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 11/15/2023] [Indexed: 12/18/2023] Open
Abstract
The conformational landscapes of peptide/human leucocyte antigen (pHLA) protein complexes encompassing tumor neoantigens provide a rationale for target selection towards autologous T cell, vaccine, and antibody-based therapeutic modalities. Here, using complementary biophysical and computational methods, we characterize recurrent RAS55-64 Q61 neoepitopes presented by the common HLA-A*01:01 allotype. We integrate sparse NMR restraints with Rosetta docking to determine the solution structure of NRASQ61K/HLA-A*01:01, which enables modeling of other common RAS55-64 neoepitopes. Hydrogen/deuterium exchange mass spectrometry experiments alongside molecular dynamics simulations reveal differences in solvent accessibility and conformational plasticity across a panel of common Q61 neoepitopes that are relevant for recognition by immunoreceptors. Finally, we predict binding and provide structural models of NRASQ61K antigens spanning the entire HLA allelic landscape, together with in vitro validation for HLA-A*01:191, HLA-B*15:01, and HLA-C*08:02. Our work provides a basis to delineate the solution surface features and immunogenicity of clinically relevant neoepitope/HLA targets for cancer therapy.
Collapse
Affiliation(s)
- Andrew C McShan
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- School of Chemistry & Biochemistry, Georgia Institute of Technology, 901 Atlantic Dr NW, Atlanta, GA, 30318, USA
| | - David Flores-Solis
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, 95064, USA
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold Straße 3A, 37075, Göttingen, Germany
| | - Yi Sun
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Samuel E Garfinkle
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jugmohit S Toor
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, 95064, USA
- Immunology Research Program, Henry Ford Cancer Institute, Henry Ford Health, Detroit, MI, 48202, USA
| | - Michael C Young
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Nikolaos G Sgourakis
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| |
Collapse
|
4
|
Li L, Peng X, Batliwala M, Bouvier M. Crystal structures of MHC class I complexes reveal the elusive intermediate conformations explored during peptide editing. Nat Commun 2023; 14:5020. [PMID: 37596268 PMCID: PMC10439229 DOI: 10.1038/s41467-023-40736-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 08/08/2023] [Indexed: 08/20/2023] Open
Abstract
Studies have suggested that MHC class I (MHC I) molecules fluctuate rapidly between numerous conformational states and these motions support peptide sampling. To date, MHC I intermediates are largely uncharacterized experimentally and remain elusive. Here, we present x-ray crystal structures of HLA-B8 loaded with 20mer peptides that show pronounced distortions at the N-terminus of the groove. Long stretches of N-terminal amino acid residues are missing in the electron density maps creating an open-ended groove. Our structures also reveal highly unusual features in MHC I-peptide interaction at the N-terminus of the groove. Molecular dynamics simulations indicate that the complexes have varying degrees of conformational flexibility in a manner consistent with the structures. We suggest that our structures have captured the remarkable molecular dynamics of MHC I-peptide interaction. The visualization of peptide-dependent conformational motions in MHC I is a major step forward in our conceptual understanding of dynamics in high-affinity peptide selection.
Collapse
Affiliation(s)
- Lenong Li
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL, 60612, USA
| | - Xubiao Peng
- Center for Quantum Technology Research and Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Mansoor Batliwala
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL, 60612, USA
| | - Marlene Bouvier
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL, 60612, USA.
| |
Collapse
|
5
|
Li L, Peng X, Batliwala M, Bouvier M. Unusual crystal structures of MHC class I complexes reveal the elusive intermediate conformations explored during peptide editing in antigen presentation. RESEARCH SQUARE 2023:rs.3.rs-2500847. [PMID: 36747752 PMCID: PMC9901037 DOI: 10.21203/rs.3.rs-2500847/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Studies have suggested that MHC class I (MHC I) molecules fluctuate rapidly between conformational states as they sample peptides for potential ligands. To date, MHC I intermediates are largely uncharacterized experimentally and remain elusive. We present x-ray crystal structures of HLA-B8 loaded with 20mer peptides that show significant conformational heterogeneity at the N-terminus of the groove. Long stretches of N-terminal residues were missing in the electron density maps creating an unstructured and widely open-ended groove. Our structures also revealed highly unusual features in MHC I and peptide conformations, and in MHC I-peptide interaction at the N-terminus of the groove. Molecular dynamics simulations showed that the complexes have varying degrees of flexibility in a manner consistent with the structures. We suggest that our structures represent transient substates explored by MHC I molecules during peptide editing. The visualization of peptide-dependent conformational flexibility in MHC I groove is a major step forward in our conceptual understanding of peptide repertoire development in antigen presentation. Our study also raises questions about the role of the N-terminus of the groove in peptide editing.
Collapse
Affiliation(s)
- Lenong Li
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL, 60612, USA
| | - Xubiao Peng
- Center for Quantum Technology Research and Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Mansoor Batliwala
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL, 60612, USA
| | - Marlene Bouvier
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL, 60612, USA
| |
Collapse
|
6
|
Tomasiak L, Karch R, Schreiner W. Conformational flexibility of a free and TCR-bound pMHC-I protein investigated by long-term molecular dynamics simulations. BMC Immunol 2022; 23:36. [PMID: 35902791 PMCID: PMC9335952 DOI: 10.1186/s12865-022-00510-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 07/13/2022] [Indexed: 11/10/2022] Open
Abstract
Background Major histocompatibility complexes (MHCs) play a crucial role in the cell-mediated adaptive immune response as they present antigenic peptides (p) which are recognized by host T cells through a complex formation of the T cell receptor (TCR) with pMHC. In the present study, we report on changes in conformational flexibility within a pMHC molecule upon TCR binding by looking at molecular dynamics (MD) simulations of the free and the TCR-bound pMHC-I protein of the LC13-HLA-B*44:05-pEEYLQAFTY complex. Results We performed long-term MD simulations with a total simulation time of 8 µs, employing 10 independent 400 ns replicas for the free and the TCR-bound pMHC system. Upon TCR ligation, we observed a reduced dynamic flexibility in the central residues of the peptide and the MHC α1-helix, altered occurrences of hydrogen bonds between the peptide and the MHC, a reduced conformational entropy of the peptide-binding groove, as well as a decreased solvent accessible surface area. Conclusions In summary, our results from 8 µs MD simulations indicate a restricted conformational space of the MHC peptide-binding groove upon TCR ligation and suggest a minimum simulation time of approximately 100 ns for biomolecules of comparable complexity to draw meaningful conclusions. Given the relatively long total simulation time, our results contribute to a more detailed view on conformational flexibility properties of the investigated free and TCR-bound pMHC-I system. Supplementary Information The online version contains supplementary material available at 10.1186/s12865-022-00510-7.
Collapse
Affiliation(s)
- Lisa Tomasiak
- Institute of Biosimulation and Bioinformatics, Center for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria
| | - Rudolf Karch
- Institute of Biosimulation and Bioinformatics, Center for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria.
| | - Wolfgang Schreiner
- Institute of Biosimulation and Bioinformatics, Center for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria
| |
Collapse
|
7
|
Walters LC, Rozbesky D, Harlos K, Quastel M, Sun H, Springer S, Rambo RP, Mohammed F, Jones EY, McMichael AJ, Gillespie GM. Primary and secondary functions of HLA-E are determined by stability and conformation of the peptide-bound complexes. Cell Rep 2022; 39:110959. [PMID: 35705051 PMCID: PMC9380258 DOI: 10.1016/j.celrep.2022.110959] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 02/11/2022] [Accepted: 05/23/2022] [Indexed: 11/19/2022] Open
Abstract
MHC-E regulates NK cells by displaying MHC class Ia signal peptides (VL9) to NKG2A:CD94 receptors. MHC-E can also present sequence-diverse, lower-affinity, pathogen-derived peptides to T cell receptors (TCRs) on CD8+ T cells. To understand these affinity differences, human MHC-E (HLA-E)-VL9 versus pathogen-derived peptide structures are compared. Small-angle X-ray scatter (SAXS) measures biophysical parameters in solution, allowing comparison with crystal structures. For HLA-E-VL9, there is concordance between SAXS and crystal parameters. In contrast, HLA-E-bound pathogen-derived peptides produce larger SAXS dimensions that reduce to their crystallographic dimensions only when excess peptide is supplied. Further crystallographic analysis demonstrates three amino acids, exclusive to MHC-E, that not only position VL9 close to the α2 helix, but also allow non-VL9 peptide binding with re-configuration of a key TCR-interacting α2 region. Thus, non-VL9-bound peptides introduce an alternative peptide-binding motif and surface recognition landscape, providing a likely basis for VL9- and non-VL9-HLA-E immune discrimination.
Collapse
Affiliation(s)
- Lucy C Walters
- Nuffield Department of Medicine Research Building, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7FZ, UK
| | - Daniel Rozbesky
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Karl Harlos
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Max Quastel
- Nuffield Department of Medicine Research Building, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7FZ, UK
| | - Hong Sun
- Nuffield Department of Medicine Research Building, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7FZ, UK; Department of Laboratory Medicine, The First Affiliated Hospital, China Medical University, Shenyang, China
| | - Sebastian Springer
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Robert P Rambo
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Fiyaz Mohammed
- Institute of Immunology and Immunotherapy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Andrew J McMichael
- Nuffield Department of Medicine Research Building, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7FZ, UK.
| | - Geraldine M Gillespie
- Nuffield Department of Medicine Research Building, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7FZ, UK.
| |
Collapse
|
8
|
Ayres CM, Baker BM. Peptide-dependent tuning of major histocompatibility complex motional properties and the consequences for cellular immunity. Curr Opin Immunol 2022; 76:102184. [PMID: 35550277 PMCID: PMC10052791 DOI: 10.1016/j.coi.2022.102184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/15/2022] [Accepted: 04/05/2022] [Indexed: 12/22/2022]
Abstract
T cell receptors (TCRs) and other receptors of the immune system recognize peptides presented by class I or class II major histocompatibility complex (MHC) proteins. Although we generally distinguish between the MHC protein and its peptide, at an atomic level the two form a structural composite, which allows peptides to influence MHC properties and vice versa. One consequence is the peptide-dependent tuning of MHC structural dynamics, which contributes to protein structural adaptability and influences how receptors identify and bind targets. Peptide-dependent tuning of MHC protein dynamics can impact processes such as antigenicity, TCR cross-reactivity, and T cell repertoire selection. Motional tuning extends beyond the binding groove, influencing peptide selection and exchange, as well as interactions with other immune receptors. Here, we review recent findings showing how peptides can affect the dynamic and adaptable nature of MHC proteins. We highlight consequences for immunity and demonstrate how MHC proteins have evolved to be highly sensitive dynamic reporters, with broad immunological consequences.
Collapse
Affiliation(s)
- Cory M Ayres
- Department of Chemistry & Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN, USA
| | - Brian M Baker
- Department of Chemistry & Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN, USA.
| |
Collapse
|
9
|
Truong HV, Sgourakis NG. Dynamics of MHC-I molecules in the antigen processing and presentation pathway. Curr Opin Immunol 2021; 70:122-128. [PMID: 34153556 PMCID: PMC8622473 DOI: 10.1016/j.coi.2021.04.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/20/2021] [Accepted: 04/30/2021] [Indexed: 01/07/2023]
Abstract
The endogenous antigen processing and presentation (APP) is a fundamental pathway found in jawed vertebrates, which allows for a set of epitope peptides sampled from the intracellular proteome to be assembled and displayed on class I proteins of the major histocompatibility complex (MHC-I). Peptide/MHC-I antigens enable different aspects of adaptive immunity to emerge, by providing a basis for recognition of self vs. non-self by T cells and Natural Killer (NK) cells. Pioneering studies of pMHC-I molecules and their higher-order protein complexes with molecular chaperones and membrane receptors have gleaned important insights into the peptide loading and antigen recognition mechanisms. While X-ray and cryoEM structures have provided us with static snapshots of different MHC-I assembly stages, complementary biophysical techniques have revealed that MHC-I molecules are highly mobile on a range of biologically relevant timescales, which bears importance for their assembly, peptide repertoire selection, membrane display and turnover. This review summarizes insights gained from experimental and simulation studies aimed at investigating MHC-I dynamics, and their functional implications.
Collapse
Affiliation(s)
- Hau V Truong
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Philadelphia, PA 19104, USA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 3401 Civic Center Blvd., Philadelphia, PA 19104, USA
| | - Nikolaos G Sgourakis
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Philadelphia, PA 19104, USA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 3401 Civic Center Blvd., Philadelphia, PA 19104, USA.
| |
Collapse
|
10
|
Jantz-Naeem N, Springer S. Venus flytrap or pas de trois? The dynamics of MHC class I molecules. Curr Opin Immunol 2021; 70:82-89. [PMID: 33993034 DOI: 10.1016/j.coi.2021.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 04/05/2021] [Accepted: 04/08/2021] [Indexed: 11/25/2022]
Abstract
The peptide binding site of major histocompatibility complex (MHC) class I molecules is natively unfolded when devoid of peptides. Peptide binding stabilizes the structure and slows the dynamics, but peptide-specific and subtype-specific motions influence, and are influenced by, interaction with assembly chaperones, the T cell receptor, and other class I-binding proteins. The molecular mechanisms of cooperation between peptide, class I heavy chain, and beta-2 microglobulin are insufficiently known but are being elucidated by nuclear magnetic resonance and other modern methods. It appears that micropolymorphic clusters of charged amino acids, often hidden in the molecule interior, determine the dynamics and thus chaperone dependence, cellular fate, and disease association of class I.
Collapse
Affiliation(s)
- Nouria Jantz-Naeem
- Department of Life Sciences and Chemistry, Jacobs University, Bremen, Germany
| | - Sebastian Springer
- Department of Life Sciences and Chemistry, Jacobs University, Bremen, Germany.
| |
Collapse
|
11
|
Ma J, Ayres CM, Hellman LM, Devlin JR, Baker BM. Dynamic allostery controls the peptide sensitivity of the Ly49C natural killer receptor. J Biol Chem 2021; 296:100686. [PMID: 33891944 PMCID: PMC8138769 DOI: 10.1016/j.jbc.2021.100686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 04/14/2021] [Accepted: 04/19/2021] [Indexed: 11/30/2022] Open
Abstract
Using a variety of activating and inhibitory receptors, natural killer (NK) cells protect against disease by eliminating cells that have downregulated class I major histocompatibility complex (MHC) proteins, such as in response to cell transformation or viral infection. The inhibitory murine NK receptor Ly49C specifically recognizes the class I MHC protein H-2Kb. Unusual among NK receptors, Ly49C exhibits a peptide-dependent sensitivity to H-2Kb recognition, which has not been explained despite detailed structural studies. To gain further insight into Ly49C peptide sensitivity, we examined Ly49C recognition biochemically and through the lens of dynamic allostery. We found that the peptide sensitivity of Ly49C arises through small differences in H-2Kb-binding affinity. Although molecular dynamics simulations supported a role for peptide-dependent protein dynamics in producing these differences in binding affinity, calorimetric measurements indicated an enthalpically as opposed to entropically driven process. A quantitative linkage analysis showed that this emerges from peptide-dependent dynamic tuning of electrostatic interactions across the Ly49C–H-2Kb interface. We propose a model whereby different peptides alter the flexibility of H-2Kb, which in turn changes the strength of electrostatic interactions across the protein–protein interface. Our results provide a quantitative assessment of how peptides alter Ly49C-binding affinity, suggest the underlying mechanism, and demonstrate peptide-driven allostery at work in class I MHC proteins. Lastly, our model provides a solution for how dynamic allostery could impact binding of some, but not all, class I MHC partners depending on the structural and chemical composition of the interfaces.
Collapse
Affiliation(s)
- Jiaqi Ma
- Department of Chemistry & Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana, USA
| | - Cory M Ayres
- Department of Chemistry & Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana, USA
| | - Lance M Hellman
- Department of Physical and Life Sciences, Nevada State College, Henderson, Nevada, USA
| | - Jason R Devlin
- Department of Chemistry & Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana, USA
| | - Brian M Baker
- Department of Chemistry & Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana, USA.
| |
Collapse
|
12
|
Smith AR, Alonso JA, Ayres CM, Singh NK, Hellman LM, Baker BM. Structurally silent peptide anchor modifications allosterically modulate T cell recognition in a receptor-dependent manner. Proc Natl Acad Sci U S A 2021; 118:e2018125118. [PMID: 33468649 PMCID: PMC7848747 DOI: 10.1073/pnas.2018125118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Presentation of peptides by class I MHC proteins underlies T cell immune responses to pathogens and cancer. The association between peptide binding affinity and immunogenicity has led to the engineering of modified peptides with improved MHC binding, with the hope that these peptides would be useful for eliciting cross-reactive immune responses directed toward their weak binding, unmodified counterparts. Increasing evidence, however, indicates that T cell receptors (TCRs) can perceive such anchor-modified peptides differently than wild-type (WT) peptides, although the scope of discrimination is unclear. We show here that even modifications at primary anchors that have no discernible structural impact can lead to substantially stronger or weaker T cell recognition depending on the TCR. Surprisingly, the effect of peptide anchor modification can be sensed by a TCR at regions distant from the site of modification, indicating a through-protein mechanism in which the anchor residue serves as an allosteric modulator for TCR binding. Our findings emphasize caution in the use and interpretation of results from anchor-modified peptides and have implications for how anchor modifications are accounted for in other circumstances, such as predicting the immunogenicity of tumor neoantigens. Our data also highlight an important need to better understand the highly tunable dynamic nature of class I MHC proteins and the impact this has on various forms of immune recognition.
Collapse
MESH Headings
- Allosteric Regulation
- Binding Sites
- Cloning, Molecular
- Crystallography, X-Ray
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Gene Expression
- Genetic Vectors/chemistry
- Genetic Vectors/metabolism
- HLA-A2 Antigen/chemistry
- HLA-A2 Antigen/genetics
- HLA-A2 Antigen/immunology
- Humans
- Jurkat Cells
- Kinetics
- Models, Molecular
- Peptides/chemistry
- Peptides/genetics
- Peptides/immunology
- Protein Binding
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Engineering
- Protein Interaction Domains and Motifs
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- Th2 Cells/cytology
- Th2 Cells/immunology
- Thermodynamics
Collapse
Affiliation(s)
- Angela R Smith
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
- Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556
| | - Jesus A Alonso
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
- Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556
| | - Cory M Ayres
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
- Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556
| | - Nishant K Singh
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
- Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556
| | - Lance M Hellman
- Department of Physical and Life Sciences, Nevada State College, Henderson, NV 89002
| | - Brian M Baker
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556;
- Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556
| |
Collapse
|
13
|
Abella JR, Antunes D, Jackson K, Lizée G, Clementi C, Kavraki LE. Markov state modeling reveals alternative unbinding pathways for peptide-MHC complexes. Proc Natl Acad Sci U S A 2020; 117:30610-30618. [PMID: 33184174 PMCID: PMC7720115 DOI: 10.1073/pnas.2007246117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Peptide binding to major histocompatibility complexes (MHCs) is a central component of the immune system, and understanding the mechanism behind stable peptide-MHC binding will aid the development of immunotherapies. While MHC binding is mostly influenced by the identity of the so-called anchor positions of the peptide, secondary interactions from nonanchor positions are known to play a role in complex stability. However, current MHC-binding prediction methods lack an analysis of the major conformational states and might underestimate the impact of secondary interactions. In this work, we present an atomically detailed analysis of peptide-MHC binding that can reveal the contributions of any interaction toward stability. We propose a simulation framework that uses both umbrella sampling and adaptive sampling to generate a Markov state model (MSM) for a coronavirus-derived peptide (QFKDNVILL), bound to one of the most prevalent MHC receptors in humans (HLA-A24:02). While our model reaffirms the importance of the anchor positions of the peptide in establishing stable interactions, our model also reveals the underestimated importance of position 4 (p4), a nonanchor position. We confirmed our results by simulating the impact of specific peptide mutations and validated these predictions through competitive binding assays. By comparing the MSM of the wild-type system with those of the D4A and D4P mutations, our modeling reveals stark differences in unbinding pathways. The analysis presented here can be applied to any peptide-MHC complex of interest with a structural model as input, representing an important step toward comprehensive modeling of the MHC class I pathway.
Collapse
Affiliation(s)
- Jayvee R Abella
- Department of Computer Science, Rice University, Houston, TX 77005
| | - Dinler Antunes
- Department of Computer Science, Rice University, Houston, TX 77005
| | - Kyle Jackson
- Department of Melanoma Medical Oncology-Research, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
| | - Gregory Lizée
- Department of Melanoma Medical Oncology-Research, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
| | - Cecilia Clementi
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005
- Department of Chemistry, Rice University, Houston, TX 77005
| | - Lydia E Kavraki
- Department of Computer Science, Rice University, Houston, TX 77005;
| |
Collapse
|
14
|
Coles CH, McMurran C, Lloyd A, Hock M, Hibbert L, Raman MCC, Hayes C, Lupardus P, Cole DK, Harper S. T cell receptor interactions with human leukocyte antigen govern indirect peptide selectivity for the cancer testis antigen MAGE-A4. J Biol Chem 2020; 295:11486-11494. [PMID: 32532817 PMCID: PMC7450119 DOI: 10.1074/jbc.ra120.014016] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/11/2020] [Indexed: 12/18/2022] Open
Abstract
T cell-mediated immunity is governed primarily by T cell receptor (TCR) recognition of peptide-human leukocyte antigen (pHLA) complexes and is essential for immunosurveillance and disease control. This interaction is generally stabilized by interactions between the HLA surface and TCR germline-encoded complementarity-determining region (CDR) loops 1 and 2, whereas peptide selectivity is guided by direct interactions with the TCR CDR3 loops. Here, we solved the structure of a newly identified TCR in complex with a clinically relevant peptide derived from the cancer testis antigen melanoma antigen-A4 (MAGE-A4). The TCR bound pHLA in a position shifted toward the peptide's N terminus. This enabled the TCR to achieve peptide selectivity via an indirect mechanism, whereby the TCR sensed the first residue of the peptide through HLA residue Trp-167, which acted as a tunable gateway. Amino acid substitutions at peptide position 1 predicted to alter the HLA Trp-167 side-chain conformation abrogated TCR binding, indicating that this indirect binding mechanism is essential for peptide recognition. These findings extend our understanding of the molecular rules that underpin antigen recognition by TCRs and have important implications for the development of TCR-based therapies.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - David K Cole
- Immunocore Ltd., Abingdon, United Kingdom .,Cardiff University School of Medicine, Cardiff, United Kingdom
| | | |
Collapse
|
15
|
Hopkins JR, Crean RM, Catici DAM, Sewell AK, Arcus VL, Van der Kamp MW, Cole DK, Pudney CR. Peptide cargo tunes a network of correlated motions in human leucocyte antigens. FEBS J 2020; 287:3777-3793. [PMID: 32134551 PMCID: PMC8651013 DOI: 10.1111/febs.15278] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 02/20/2020] [Accepted: 03/03/2020] [Indexed: 11/28/2022]
Abstract
Most biomolecular interactions are typically thought to increase the (local) rigidity of a complex, for example, in drug‐target binding. However, detailed analysis of specific biomolecular complexes can reveal a more subtle interplay between binding and rigidity. Here, we focussed on the human leucocyte antigen (HLA), which plays a crucial role in the adaptive immune system by presenting peptides for recognition by the αβ T‐cell receptor (TCR). The role that the peptide plays in tuning HLA flexibility during TCR recognition is potentially crucial in determining the functional outcome of an immune response, with obvious relevance to the growing list of immunotherapies that target the T‐cell compartment. We have applied high‐pressure/temperature perturbation experiments, combined with molecular dynamics simulations, to explore the drivers that affect molecular flexibility for a series of different peptide–HLA complexes. We find that different peptide sequences affect peptide–HLA flexibility in different ways, with the peptide cargo tuning a network of correlated motions throughout the pHLA complex, including in areas remote from the peptide‐binding interface, in a manner that could influence T‐cell antigen discrimination.
Collapse
Affiliation(s)
- Jade R Hopkins
- Division of Infection and Immunity, School of Medicine, Cardiff University, UK
| | - Rory M Crean
- Department of Biology and Biochemistry, University of Bath, UK.,Doctoral Training Centre in Sustainable Chemical Technologies, University of Bath, UK
| | | | - Andrew K Sewell
- Division of Infection and Immunity, School of Medicine, Cardiff University, UK
| | - Vickery L Arcus
- School of Science, Faculty of Science and Engineering, University of Waikato, Hamilton, New Zealand
| | | | - David K Cole
- Division of Infection and Immunity, School of Medicine, Cardiff University, UK
| | - Christopher R Pudney
- Department of Biology and Biochemistry, University of Bath, UK.,Centre for Therapeutic Innovation, University of Bath, UK
| |
Collapse
|
16
|
Molecular determinants of chaperone interactions on MHC-I for folding and antigen repertoire selection. Proc Natl Acad Sci U S A 2019; 116:25602-25613. [PMID: 31796585 PMCID: PMC6926029 DOI: 10.1073/pnas.1915562116] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The interplay between a highly polymorphic set of MHC-I alleles and molecular chaperones shapes the repertoire of peptide antigens displayed on the cell surface for T cell surveillance. Here, we demonstrate that the molecular chaperone TAP-binding protein related (TAPBPR) associates with a broad range of partially folded MHC-I species inside the cell. Bimolecular fluorescence complementation and deep mutational scanning reveal that TAPBPR recognition is polarized toward the α2 domain of the peptide-binding groove, and depends on the formation of a conserved MHC-I disulfide epitope in the α2 domain. Conversely, thermodynamic measurements of TAPBPR binding for a representative set of properly conformed, peptide-loaded molecules suggest a narrower MHC-I specificity range. Using solution NMR, we find that the extent of dynamics at "hotspot" surfaces confers TAPBPR recognition of a sparsely populated MHC-I state attained through a global conformational change. Consistently, restriction of MHC-I groove plasticity through the introduction of a disulfide bond between the α1/α2 helices abrogates TAPBPR binding, both in solution and on a cellular membrane, while intracellular binding is tolerant of many destabilizing MHC-I substitutions. Our data support parallel TAPBPR functions of 1) chaperoning unstable MHC-I molecules with broad allele-specificity at early stages of their folding process, and 2) editing the peptide cargo of properly conformed MHC-I molecules en route to the surface, which demonstrates a narrower specificity. Our results suggest that TAPBPR exploits localized structural adaptations, both near and distant to the peptide-binding groove, to selectively recognize discrete conformational states sampled by MHC-I alleles, toward editing the repertoire of displayed antigens.
Collapse
|
17
|
Ayres CM, Abualrous ET, Bailey A, Abraham C, Hellman LM, Corcelli SA, Noé F, Elliott T, Baker BM. Dynamically Driven Allostery in MHC Proteins: Peptide-Dependent Tuning of Class I MHC Global Flexibility. Front Immunol 2019; 10:966. [PMID: 31130956 PMCID: PMC6509175 DOI: 10.3389/fimmu.2019.00966] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 04/15/2019] [Indexed: 11/21/2022] Open
Abstract
T cell receptor (TCR) recognition of antigenic peptides bound and presented by class I major histocompatibility complex (MHC) proteins underlies the cytotoxic immune response to diseased cells. Crystallographic structures of TCR-peptide/MHC complexes have demonstrated how TCRs simultaneously interact with both the peptide and the MHC protein. However, it is increasingly recognized that, beyond serving as a static platform for peptide presentation, the physical properties of class I MHC proteins are tuned by different peptides in ways that are not always structurally visible. These include MHC protein motions, or dynamics, which are believed to influence interactions with a variety of MHC-binding proteins, including not only TCRs, but other activating and inhibitory receptors as well as components of the peptide loading machinery. Here, we investigated the mechanisms by which peptides tune the dynamics of the common class I MHC protein HLA-A2. By examining more than 50 lengthy molecular dynamics simulations of HLA-A2 presenting different peptides, we identified regions susceptible to dynamic tuning, including regions in the peptide binding domain as well as the distal α3 domain. Further analyses of the simulations illuminated mechanisms by which the influences of different peptides are communicated throughout the protein, and involve regions of the peptide binding groove, the β2-microglobulin subunit, and the α3 domain. Overall, our results demonstrate that the class I MHC protein is a highly tunable peptide sensor whose physical properties vary considerably with bound peptide. Our data provides insight into the underlying principles and suggest a role for dynamically driven allostery in the immunological function of MHC proteins.
Collapse
Affiliation(s)
- Cory M Ayres
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States.,Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States
| | - Esam T Abualrous
- Computational Molecular Biology Group, Institute for Mathematics, Freie Universität Berlin, Berlin, Germany
| | - Alistair Bailey
- Institute for Life Sciences and Centre for Cancer Immunology, University of Southampton, Southampton, United Kingdom
| | - Christian Abraham
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States.,Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States
| | - Lance M Hellman
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States.,Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States
| | - Steven A Corcelli
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States
| | - Frank Noé
- Computational Molecular Biology Group, Institute for Mathematics, Freie Universität Berlin, Berlin, Germany
| | - Tim Elliott
- Institute for Life Sciences and Centre for Cancer Immunology, University of Southampton, Southampton, United Kingdom
| | - Brian M Baker
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States.,Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States
| |
Collapse
|
18
|
Buckle AM, Borg NA. Integrating Experiment and Theory to Understand TCR-pMHC Dynamics. Front Immunol 2018; 9:2898. [PMID: 30581442 PMCID: PMC6293202 DOI: 10.3389/fimmu.2018.02898] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 11/26/2018] [Indexed: 11/13/2022] Open
Abstract
The conformational dynamism of proteins is well established. Rather than having a single structure, proteins are more accurately described as a conformational ensemble that exists across a rugged energy landscape, where different conformational sub-states interconvert. The interaction between αβ T cell receptors (TCR) and cognate peptide-MHC (pMHC) is no exception, and is a dynamic process that involves substantial conformational change. This review focuses on technological advances that have begun to establish the role of conformational dynamics and dynamic allostery in TCR recognition of the pMHC and the early stages of signaling. We discuss how the marriage of molecular dynamics (MD) simulations with experimental techniques provides us with new ways to dissect and interpret the process of TCR ligation. Notably, application of simulation techniques lags behind other fields, but is predicted to make substantial contributions. Finally, we highlight integrated approaches that are being used to shed light on some of the key outstanding questions in the early events leading to TCR signaling.
Collapse
Affiliation(s)
- Ashley M Buckle
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Natalie A Borg
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| |
Collapse
|
19
|
Riley TP, Baker BM. The intersection of affinity and specificity in the development and optimization of T cell receptor based therapeutics. Semin Cell Dev Biol 2018; 84:30-41. [DOI: 10.1016/j.semcdb.2017.10.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 10/07/2017] [Accepted: 10/17/2017] [Indexed: 12/29/2022]
|
20
|
Natarajan K, Jiang J, May NA, Mage MG, Boyd LF, McShan AC, Sgourakis NG, Bax A, Margulies DH. The Role of Molecular Flexibility in Antigen Presentation and T Cell Receptor-Mediated Signaling. Front Immunol 2018; 9:1657. [PMID: 30065727 PMCID: PMC6056622 DOI: 10.3389/fimmu.2018.01657] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 07/04/2018] [Indexed: 01/20/2023] Open
Abstract
Antigen presentation is a cellular process that involves a number of steps, beginning with the production of peptides by proteolysis or aberrant synthesis and the delivery of peptides to cellular compartments where they are loaded on MHC class I (MHC-I) or MHC class II (MHC-II) molecules. The selective loading and editing of high-affinity immunodominant antigens is orchestrated by molecular chaperones: tapasin/TAP-binding protein, related for MHC-I and HLA-DM for MHC-II. Once peptide/MHC (pMHC) complexes are assembled, following various steps of quality control, they are delivered to the cell surface, where they are available for identification by αβ receptors on CD8+ or CD4+ T lymphocytes. In addition, recognition of cell surface peptide/MHC-I complexes by natural killer cell receptors plays a regulatory role in some aspects of the innate immune response. Many of the components of the pathways of antigen processing and presentation and of T cell receptor (TCR)-mediated signaling have been studied extensively by biochemical, genetic, immunological, and structural approaches over the past several decades. Until recently, however, dynamic aspects of the interactions of peptide with MHC, MHC with molecular chaperones, or of pMHC with TCR have been difficult to address experimentally, although computational approaches such as molecular dynamics (MD) simulations have been illuminating. Studies exploiting X-ray crystallography, cryo-electron microscopy, and multidimensional nuclear magnetic resonance (NMR) spectroscopy are beginning to reveal the importance of molecular flexibility as it pertains to peptide loading onto MHC molecules, the interactions between pMHC and TCR, and subsequent TCR-mediated signals. In addition, recent structural and dynamic insights into how molecular chaperones define peptide selection and fine-tune the MHC displayed antigen repertoire are discussed. Here, we offer a review of current knowledge that highlights experimental data obtained by X-ray crystallography and multidimensional NMR methodologies. Collectively, these findings strongly support a multifaceted role for protein plasticity and conformational dynamics throughout the antigen processing and presentation pathway in dictating antigen selection and recognition.
Collapse
Affiliation(s)
- Kannan Natarajan
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Jiansheng Jiang
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Nathan A May
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Michael G Mage
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Lisa F Boyd
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Andrew C McShan
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA, United States
| | - Nikolaos G Sgourakis
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - David H Margulies
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| |
Collapse
|
21
|
Fodor J, Riley BT, Borg NA, Buckle AM. Previously Hidden Dynamics at the TCR-Peptide-MHC Interface Revealed. THE JOURNAL OF IMMUNOLOGY 2018; 200:4134-4145. [PMID: 29728507 DOI: 10.4049/jimmunol.1800315] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 04/10/2018] [Indexed: 12/28/2022]
Abstract
A structural characterization of the interaction between αβ TCRs and cognate peptide-MHC (pMHC) is central to understanding adaptive T cell-mediated immunity. X-ray crystallography, although the source of much structural data, traditionally provides only a static snapshot of the protein. Given the emerging evidence for the important role of conformational dynamics in protein function, we interrogated 309 crystallographic structures of pMHC complexes using ensemble refinement, a technique that can extract dynamic information from the x-ray data. Focusing on a subset of human pMHC class I systems, we found that in many cases, ensemble methods were able to uncover previously hidden evidence of significant conformational plasticity, thereby revealing additional information that can build upon and significantly enhance functional interpretations that are based on a single static structure. Notable examples include the interpretation of differences in the disease association of HLA subtypes, the relationship between peptide prominence and TCR recognition, the role of conformational flexibility in vaccine design, and the discrimination between induced fit and conformational selection models of TCR binding. We show that the currently widespread practice of analyzing pMHC interactions via the study of a single crystallographic structure does not make use of pertinent and easily accessible information from x-ray data concerning alternative protein conformations. This new analysis therefore not only highlights the capacity for ensemble methods to significantly enrich the interpretation of decades of structural data but also provides previously missing information concerning the dynamics of existing characterized TCR-pMHC interactions.
Collapse
Affiliation(s)
- James Fodor
- Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia; and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Blake T Riley
- Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia; and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Natalie A Borg
- Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia; and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Ashley M Buckle
- Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia; and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| |
Collapse
|
22
|
Antunes DA, Devaurs D, Moll M, Lizée G, Kavraki LE. General Prediction of Peptide-MHC Binding Modes Using Incremental Docking: A Proof of Concept. Sci Rep 2018. [PMID: 29531253 PMCID: PMC5847594 DOI: 10.1038/s41598-018-22173-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The class I major histocompatibility complex (MHC) is capable of binding peptides derived from intracellular proteins and displaying them at the cell surface. The recognition of these peptide-MHC (pMHC) complexes by T-cells is the cornerstone of cellular immunity, enabling the elimination of infected or tumoral cells. T-cell-based immunotherapies against cancer, which leverage this mechanism, can greatly benefit from structural analyses of pMHC complexes. Several attempts have been made to use molecular docking for such analyses, but pMHC structure remains too challenging for even state-of-the-art docking tools. To overcome these limitations, we describe the use of an incremental meta-docking approach for structural prediction of pMHC complexes. Previous methods applied in this context used specific constraints to reduce the complexity of this prediction problem, at the expense of generality. Our strategy makes no assumption and can potentially be used to predict binding modes for any pMHC complex. Our method has been tested in a re-docking experiment, reproducing the binding modes of 25 pMHC complexes whose crystal structures are available. This study is a proof of concept that incremental docking strategies can lead to general geometry prediction of pMHC complexes, with potential applications for immunotherapy against cancer or infectious diseases.
Collapse
Affiliation(s)
- Dinler A Antunes
- Department of Computer Science, Rice University, Houston, TX, 77005, USA
| | - Didier Devaurs
- Department of Computer Science, Rice University, Houston, TX, 77005, USA
| | - Mark Moll
- Department of Computer Science, Rice University, Houston, TX, 77005, USA
| | - Gregory Lizée
- Department of Melanoma Medical Oncology - Research, The University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Lydia E Kavraki
- Department of Computer Science, Rice University, Houston, TX, 77005, USA.
| |
Collapse
|
23
|
van Hateren A, Anderson M, Bailey A, Werner JM, Skipp P, Elliott T. Direct evidence for conformational dynamics in major histocompatibility complex class I molecules. J Biol Chem 2017; 292:20255-20269. [PMID: 29021251 PMCID: PMC5724011 DOI: 10.1074/jbc.m117.809624] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 09/25/2017] [Indexed: 12/19/2022] Open
Abstract
Major histocompatibility complex class I molecules (MHC I) help protect jawed vertebrates by binding and presenting immunogenic peptides to cytotoxic T lymphocytes. Peptides are selected from a large diversity present in the endoplasmic reticulum. However, only a limited number of peptides complement the polymorphic MHC specificity determining pockets in a way that leads to high-affinity peptide binding and efficient antigen presentation. MHC I molecules possess an intrinsic ability to discriminate between peptides, which varies in efficiency between allotypes, but the mechanism of selection is unknown. Elucidation of the selection mechanism is likely to benefit future immune-modulatory therapies. Evidence suggests peptide selection involves transient adoption of alternative, presumably higher energy conformations than native peptide-MHC complexes. However, the instability of peptide-receptive MHC molecules has hindered characterization of such conformational plasticity. To investigate the dynamic nature of MHC, we refolded MHC proteins with peptides that can be hydrolyzed by UV light and thus released. We compared the resultant peptide-receptive MHC molecules with non-hydrolyzed peptide-loaded MHC complexes by monitoring the exchange of hydrogen for deuterium in solution. We found differences in hydrogen-deuterium exchange between peptide-loaded and peptide-receptive molecules that were negated by the addition of peptide to peptide-receptive MHC molecules. Peptide hydrolysis caused significant increases in hydrogen-deuterium exchange in sub-regions of the peptide-binding domain and smaller increases elsewhere, including in the α3 domain and the non-covalently associated β2-microglobulin molecule, demonstrating long-range dynamic communication. Comparing two MHC allotypes revealed allotype-specific differences in hydrogen-deuterium exchange, consistent with the notion that MHC I plasticity underpins peptide selection.
Collapse
Affiliation(s)
- Andy van Hateren
- Institute for Life Sciences and Centre for Cancer Immunology, Faculty of Medicine, Southampton SO17 1BJ
| | - Malcolm Anderson
- Waters Corporation, Stamford Avenue, Altrincham Road, Wilmslow SK9 4AX, United Kingdom
| | - Alistair Bailey
- Institute for Life Sciences and Centre for Cancer Immunology, Faculty of Medicine, Southampton SO17 1BJ; Centre for Proteomic Research, Biological Sciences, and Institute for Life Sciences, Southampton SO17 1BJ
| | - Jörn M Werner
- Institute for Life Sciences, Centre for Biological Sciences, and Faculty of Natural and Environmental Sciences, University of Southampton, Building 85, Southampton SO17 1BJ
| | - Paul Skipp
- Centre for Proteomic Research, Biological Sciences, and Institute for Life Sciences, Southampton SO17 1BJ
| | - Tim Elliott
- Institute for Life Sciences and Centre for Cancer Immunology, Faculty of Medicine, Southampton SO17 1BJ.
| |
Collapse
|
24
|
Jiao Y, Tan S, Xiong J. Proteomic changes of CD4 +/CD25 +/forkhead box p3 + regulatory T cells in a 30-day rat model of sepsis survival. Exp Ther Med 2017; 14:5619-5628. [PMID: 29285101 DOI: 10.3892/etm.2017.5233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 07/20/2017] [Indexed: 02/07/2023] Open
Abstract
Sepsis is defined as life threatening organ dysfunction arising from a dysregulated host response to infection. The outcomes of sepsis include early mortality, delayed mortality and recovery, and depend on the inflammatory response. Previous studies have demonstrated that regulatory T cells (Tregs) are important in determining the outcome of sepsis, as their suppressive function serves a role in maintaining immune homeostasis. However, Treg-mediated immunosuppression during the course of sepsis remains unclear and little is known about the survival of patients following diagnosis. Studying the survivors of sepsis may explain the mechanisms of natural recovery. Therefore, a 30-day rat model of sepsis survival was established in the current study. Cluster of differentiation CD4+/CD25+/forkhead box p3+ Tregs were isolated from the blood and spleens of rats undergoing cecal ligation and puncture or sham surgery, using flow cytometry. Proteomic analysis was performed using nano high-performance liquid chromatography-mass spectrometry. Several different biological pathways associated with uncommon differentially-expressed proteins were identified in the blood and spleen survivor and sham groups. Extracellular-regulated kinase/mitogen-activated protein kinase, as well as integrin and actin cytoskeletal pathway elements, including Ras-related protein 1b, talin 1 and filamin A, were associated with Tregs in the blood. Pathway elements associated with cell cycle regulators in the B-cell translocation gene family of proteins, tumor necrosis factor receptor superfamily member 4, Hippo signaling, P70-S6 kinase 1, phosphatidylinositol 3-kinase/protein kinase B signaling and 1,25-dihydroxyvitamin D3 biosynthesis were associated with Tregs from the spleen including phosphatase 2A activator regulatory factor 4, histone arginine methyltransferase, CD4, major histocompatibility complex class I antigens, 14-3-3 protein θ and nicotinamide adenine dinucleotide phosphate cytochrome P450 reductase. These results explain the mechanism by which Tregs naturally recover and indicates that Tregs in the blood and spleen vary. Differentially-expressed proteins serving a role in these pathways provide additional insight for the identification of new targets for the diagnosis and treatment of sepsis.
Collapse
Affiliation(s)
- Yuxia Jiao
- Department of Anesthesiology, The Second Hospital of Dalian Medical University, Dalian, Liaoning 116027, P.R. China
| | - Siqi Tan
- Department of Anesthesiology, The Second Hospital of Dalian Medical University, Dalian, Liaoning 116027, P.R. China
| | - Junyu Xiong
- Department of Anesthesiology, The Second Hospital of Dalian Medical University, Dalian, Liaoning 116027, P.R. China
| |
Collapse
|
25
|
Ayres CM, Corcelli SA, Baker BM. Peptide and Peptide-Dependent Motions in MHC Proteins: Immunological Implications and Biophysical Underpinnings. Front Immunol 2017; 8:935. [PMID: 28824655 PMCID: PMC5545744 DOI: 10.3389/fimmu.2017.00935] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 07/21/2017] [Indexed: 01/28/2023] Open
Abstract
Structural biology of peptides presented by class I and class II MHC proteins has transformed immunology, impacting our understanding of fundamental immune mechanisms and allowing researchers to rationalize immunogenicity and design novel vaccines. However, proteins are not static structures as often inferred from crystallographic structures. Their components move and breathe individually and collectively over a range of timescales. Peptides bound within MHC peptide-binding grooves are no exception and their motions have been shown to impact recognition by T cell and other receptors in ways that influence function. Furthermore, peptides tune the motions of MHC proteins themselves, which impacts recognition of peptide/MHC complexes by other proteins. Here, we review the motional properties of peptides in MHC binding grooves and discuss how peptide properties can influence MHC motions. We briefly review theoretical concepts about protein motion and highlight key data that illustrate immunological consequences. We focus primarily on class I systems due to greater availability of data, but segue into class II systems as the concepts and consequences overlap. We suggest that characterization of the dynamic “energy landscapes” of peptide/MHC complexes and the resulting functional consequences is one of the next frontiers in structural immunology.
Collapse
Affiliation(s)
- Cory M Ayres
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States.,Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States
| | - Steven A Corcelli
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States
| | - Brian M Baker
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States.,Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States
| |
Collapse
|
26
|
Ayres CM, Riley TP, Corcelli SA, Baker BM. Modeling Sequence-Dependent Peptide Fluctuations in Immunologic Recognition. J Chem Inf Model 2017; 57:1990-1998. [PMID: 28696685 DOI: 10.1021/acs.jcim.7b00118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In cellular immunity, T cells recognize peptide antigens bound and presented by major histocompatibility complex (MHC) proteins. The motions of peptides bound to MHC proteins play a significant role in determining immunogenicity. However, existing approaches for investigating peptide/MHC motional dynamics are challenging or of low throughput, hindering the development of algorithms for predicting immunogenicity from large databases, such as those of tumor or genetically unstable viral genomes. We addressed this by performing extensive molecular dynamics simulations on a large structural database of peptides bound to the most commonly expressed human class-I MHC protein, HLA-A*0201. The simulations reproduced experimental indicators of motion and were used to generate simple models for predicting site-specific, rapid motions of bound peptides through differences in their sequence and chemical composition alone. The models can easily be applied on their own or incorporated into immunogenicity prediction algorithms. Beyond their predictive power, the models provide insight into how amino acid substitutions can influence peptide and protein motions and how dynamic information is communicated across peptides. They also indicate a link between peptide rigidity and hydrophobicity, two features known to be important in influencing cellular immune responses.
Collapse
Affiliation(s)
- Cory M Ayres
- Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - Timothy P Riley
- Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - Steven A Corcelli
- Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - Brian M Baker
- Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States
| |
Collapse
|
27
|
Merkle PS, Irving M, Hongjian S, Ferber M, Jørgensen TJD, Scholten K, Luescher I, Coukos G, Zoete V, Cuendet MA, Michielin O, Rand KD. The T-Cell Receptor Can Bind to the Peptide-Bound Major Histocompatibility Complex and Uncomplexed β2-Microglobulin through Distinct Binding Sites. Biochemistry 2017; 56:3945-3961. [DOI: 10.1021/acs.biochem.7b00385] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Patrick S. Merkle
- Department
of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Melita Irving
- Swiss Institute of Bioinformatics, Bâtiment Génopode, UNIL Sorge, 1015 Lausanne, Switzerland
- Ludwig
Branch for Cancer Research, University of Lausanne, 1015 Lausanne, Switzerland
| | - Song Hongjian
- Department
of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Mathias Ferber
- Swiss Institute of Bioinformatics, Bâtiment Génopode, UNIL Sorge, 1015 Lausanne, Switzerland
| | - Thomas J. D. Jørgensen
- Department
of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Kirsten Scholten
- Ludwig
Branch for Cancer Research, University of Lausanne, 1015 Lausanne, Switzerland
| | - Immanuel Luescher
- Ludwig
Branch for Cancer Research, University of Lausanne, 1015 Lausanne, Switzerland
| | - George Coukos
- Ludwig
Branch for Cancer Research, University of Lausanne, 1015 Lausanne, Switzerland
| | - Vincent Zoete
- Swiss Institute of Bioinformatics, Bâtiment Génopode, UNIL Sorge, 1015 Lausanne, Switzerland
| | - Michel A. Cuendet
- Swiss Institute of Bioinformatics, Bâtiment Génopode, UNIL Sorge, 1015 Lausanne, Switzerland
- Department
of Physiology and Biophysics, Weill Cornell Medical College, 1300
York Avenue, New York, New
York 10065, United States
| | - Olivier Michielin
- Swiss Institute of Bioinformatics, Bâtiment Génopode, UNIL Sorge, 1015 Lausanne, Switzerland
| | - Kasper D. Rand
- Department
of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark
| |
Collapse
|
28
|
Yanaka S, Sugase K. Exploration of the Conformational Dynamics of Major Histocompatibility Complex Molecules. Front Immunol 2017; 8:632. [PMID: 28611781 PMCID: PMC5446982 DOI: 10.3389/fimmu.2017.00632] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 05/12/2017] [Indexed: 12/02/2022] Open
Abstract
Major histocompatibility complex (MHC) molecules are loaded with a wide variety of self- and non-self-peptides in their binding grooves and present these to T cell receptors (TCRs) in order to activate the adaptive immune system. A large number of crystal structures of different MHC alleles with different bound peptides have been determined, and they have been found to be quite similar to one another regardless of the bound peptide sequence. The structures do not change markedly even when forming complexes with TCRs. Nonetheless, the degree of TCR activation does differ markedly depending on the peptide presented by the MHC. Recent structural studies in solution rather than as crystals have suggested that the conformational dynamics of MHC molecules may be responsible for the MHC stability differences. Furthermore, it was shown that the conformational dynamics of MHC molecules is important for peptide loading and presentation to TCR. Here, we describe the static and dynamic structures of MHC molecules and appropriate methods to analyze them. We focus particularly on nuclear magnetic resonance (NMR), one of the most powerful tools to study dynamic properties of proteins. The number of such studies in the literature is limited, but in this review, we show that NMR is valuable for elucidating the structural dynamics of MHC molecules.
Collapse
Affiliation(s)
- Saeko Yanaka
- Department of Life and Coordination-Complex Molecular Science, Biomolecular Functions, Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Japan
| | - Kenji Sugase
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| |
Collapse
|
29
|
Schmidt J, Guillaume P, Dojcinovic D, Karbach J, Coukos G, Luescher I. In silico and cell-based analyses reveal strong divergence between prediction and observation of T-cell-recognized tumor antigen T-cell epitopes. J Biol Chem 2017; 292:11840-11849. [PMID: 28536262 DOI: 10.1074/jbc.m117.789511] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/11/2017] [Indexed: 11/06/2022] Open
Abstract
Tumor exomes provide comprehensive information on mutated, overexpressed genes and aberrant splicing, which can be exploited for personalized cancer immunotherapy. Of particular interest are mutated tumor antigen T-cell epitopes, because neoepitope-specific T cells often are tumoricidal. However, identifying tumor-specific T-cell epitopes is a major challenge. A widely used strategy relies on initial prediction of human leukocyte antigen-binding peptides by in silico algorithms, but the predictive power of this approach is unclear. Here, we used the human tumor antigen NY-ESO-1 (ESO) and the human leukocyte antigen variant HLA-A*0201 (A2) as a model and predicted in silico the 41 highest-affinity, A2-binding 8-11-mer peptides and assessed their binding, kinetic complex stability, and immunogenicity in A2-transgenic mice and on peripheral blood mononuclear cells from ESO-vaccinated melanoma patients. We found that 19 of the peptides strongly bound to A2, 10 of which formed stable A2-peptide complexes and induced CD8+ T cells in A2-transgenic mice. However, only 5 of the peptides induced cognate T cells in humans; these peptides exhibited strong binding and complex stability and contained multiple large hydrophobic and aromatic amino acids. These results were not predicted by in silico algorithms and provide new clues to improving T-cell epitope identification. In conclusion, our findings indicate that only a small fraction of in silico-predicted A2-binding ESO peptides are immunogenic in humans, namely those that have high peptide-binding strength and complex stability. This observation highlights the need for improving in silico predictions of peptide immunogenicity.
Collapse
Affiliation(s)
- Julien Schmidt
- Ludwig Institute for Cancer Research, University of Lausanne, 1066 Epalinges, Switzerland
| | - Philippe Guillaume
- Ludwig Institute for Cancer Research, University of Lausanne, 1066 Epalinges, Switzerland
| | - Danijel Dojcinovic
- Ludwig Institute for Cancer Research, University of Lausanne, 1066 Epalinges, Switzerland
| | | | - George Coukos
- Ludwig Institute for Cancer Research, University of Lausanne, 1066 Epalinges, Switzerland; Department of Oncology, University Hospital of Lausanne, 1011 Lausanne, Switzerland
| | - Immanuel Luescher
- Ludwig Institute for Cancer Research, University of Lausanne, 1066 Epalinges, Switzerland.
| |
Collapse
|
30
|
Conformational Variants of the Individual HLA-I Antigens on Luminex Single Antigen Beads Used in Monitoring HLA Antibodies: Problems and Solutions. Transplantation 2017; 101:764-777. [PMID: 27495776 DOI: 10.1097/tp.0000000000001420] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Single antigen beads (SAB) are used for monitoring HLA antibodies in pretransplant and posttransplant patients despite the discrepancy between virtual and actual crossmatch results and transplant outcomes. This discrepancy can be attributed to the presence of conformational variants of HLA-I on SAB, assessment of which would increase the concordance between SAB and flow cytometry crossmatch (FCXM) results, thus enabling improved organ accessibility for the waiting list patients and a better prediction of antibody-mediated rejection. METHODS The conformational variants were examined on HLA-I beads, iBeads, acid-/alkali-treated beads, and T cells using HLA-I monoclonal antibodies (W6/32, TFL-006, and heavy chain (HC)-10). RESULTS The affinity of the monoclonal antibodies against HLA-I beads confirmed the presence and heterogeneous density of peptide-associated β2-microglobulin-associated HLA HC (pepA-β2aHC), peptide-free-β2aHC (pepF-β2aHC), and β2-free HC (β2fHC) on every single antigen-coated bead. In contrast, iBeads harbor a high density of pepA-β2aHC, low density of pepF-β2aHC, and are lacking β2fHC. The FCXM analyses confirmed the prevalence of pepA-β2aHC, but not pepF-β2aHC or β2fHC on resting T cells. CONCLUSIONS The strength of a donor-specific antibody should be assessed with a bead-specific mean fluorescence intensity cutoff based on TFL-006 reactivity against HLA-I beads, and HC-10 against iBeads, where the β2fHC or pepF-β2aHC normalized donor-specific antibody level would reveal the true anti-pepA-β2aHC reactivity associated with positive FCXM.
Collapse
|
31
|
Wieczorek M, Abualrous ET, Sticht J, Álvaro-Benito M, Stolzenberg S, Noé F, Freund C. Major Histocompatibility Complex (MHC) Class I and MHC Class II Proteins: Conformational Plasticity in Antigen Presentation. Front Immunol 2017. [PMID: 28367149 DOI: 10.3389/fimmu.2017.00292.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Antigen presentation by major histocompatibility complex (MHC) proteins is essential for adaptive immunity. Prior to presentation, peptides need to be generated from proteins that are either produced by the cell's own translational machinery or that are funneled into the endo-lysosomal vesicular system. The prolonged interaction between a T cell receptor and specific pMHC complexes, after an extensive search process in secondary lymphatic organs, eventually triggers T cells to proliferate and to mount a specific cellular immune response. Once processed, the peptide repertoire presented by MHC proteins largely depends on structural features of the binding groove of each particular MHC allelic variant. Additionally, two peptide editors-tapasin for class I and HLA-DM for class II-contribute to the shaping of the presented peptidome by favoring the binding of high-affinity antigens. Although there is a vast amount of biochemical and structural information, the mechanism of the catalyzed peptide exchange for MHC class I and class II proteins still remains controversial, and it is not well understood why certain MHC allelic variants are more susceptible to peptide editing than others. Recent studies predict a high impact of protein intermediate states on MHC allele-specific peptide presentation, which implies a profound influence of MHC dynamics on the phenomenon of immunodominance and the development of autoimmune diseases. Here, we review the recent literature that describe MHC class I and II dynamics from a theoretical and experimental point of view and we highlight the similarities between MHC class I and class II dynamics despite the distinct functions they fulfill in adaptive immunity.
Collapse
Affiliation(s)
- Marek Wieczorek
- Protein Biochemistry, Institute for Biochemistry, Freie Universität Berlin , Berlin , Germany
| | - Esam T Abualrous
- Computational Molecular Biology Group, Institute for Mathematics , Berlin , Germany
| | - Jana Sticht
- Protein Biochemistry, Institute for Biochemistry, Freie Universität Berlin , Berlin , Germany
| | - Miguel Álvaro-Benito
- Protein Biochemistry, Institute for Biochemistry, Freie Universität Berlin , Berlin , Germany
| | | | - Frank Noé
- Computational Molecular Biology Group, Institute for Mathematics , Berlin , Germany
| | - Christian Freund
- Protein Biochemistry, Institute for Biochemistry, Freie Universität Berlin , Berlin , Germany
| |
Collapse
|
32
|
Wieczorek M, Abualrous ET, Sticht J, Álvaro-Benito M, Stolzenberg S, Noé F, Freund C. Major Histocompatibility Complex (MHC) Class I and MHC Class II Proteins: Conformational Plasticity in Antigen Presentation. Front Immunol 2017; 8:292. [PMID: 28367149 PMCID: PMC5355494 DOI: 10.3389/fimmu.2017.00292] [Citation(s) in RCA: 552] [Impact Index Per Article: 78.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 02/28/2017] [Indexed: 11/21/2022] Open
Abstract
Antigen presentation by major histocompatibility complex (MHC) proteins is essential for adaptive immunity. Prior to presentation, peptides need to be generated from proteins that are either produced by the cell’s own translational machinery or that are funneled into the endo-lysosomal vesicular system. The prolonged interaction between a T cell receptor and specific pMHC complexes, after an extensive search process in secondary lymphatic organs, eventually triggers T cells to proliferate and to mount a specific cellular immune response. Once processed, the peptide repertoire presented by MHC proteins largely depends on structural features of the binding groove of each particular MHC allelic variant. Additionally, two peptide editors—tapasin for class I and HLA-DM for class II—contribute to the shaping of the presented peptidome by favoring the binding of high-affinity antigens. Although there is a vast amount of biochemical and structural information, the mechanism of the catalyzed peptide exchange for MHC class I and class II proteins still remains controversial, and it is not well understood why certain MHC allelic variants are more susceptible to peptide editing than others. Recent studies predict a high impact of protein intermediate states on MHC allele-specific peptide presentation, which implies a profound influence of MHC dynamics on the phenomenon of immunodominance and the development of autoimmune diseases. Here, we review the recent literature that describe MHC class I and II dynamics from a theoretical and experimental point of view and we highlight the similarities between MHC class I and class II dynamics despite the distinct functions they fulfill in adaptive immunity.
Collapse
Affiliation(s)
- Marek Wieczorek
- Protein Biochemistry, Institute for Biochemistry, Freie Universität Berlin , Berlin , Germany
| | - Esam T Abualrous
- Computational Molecular Biology Group, Institute for Mathematics , Berlin , Germany
| | - Jana Sticht
- Protein Biochemistry, Institute for Biochemistry, Freie Universität Berlin , Berlin , Germany
| | - Miguel Álvaro-Benito
- Protein Biochemistry, Institute for Biochemistry, Freie Universität Berlin , Berlin , Germany
| | | | - Frank Noé
- Computational Molecular Biology Group, Institute for Mathematics , Berlin , Germany
| | - Christian Freund
- Protein Biochemistry, Institute for Biochemistry, Freie Universität Berlin , Berlin , Germany
| |
Collapse
|
33
|
Serçinoğlu O, Ozbek P. Computational characterization of residue couplings and micropolymorphism-induced changes in the dynamics of two differentially disease-associated human MHC class-I alleles. J Biomol Struct Dyn 2017; 36:724-740. [DOI: 10.1080/07391102.2017.1295884] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Onur Serçinoğlu
- Department of Bioengineering, Institute of Pure and Applied Sciences, Marmara University, Istanbul, Turkey
- Faculty of Engineering, Department of Bioengineering, Marmara University, Istanbul, Turkey
| | - Pemra Ozbek
- Faculty of Engineering, Department of Bioengineering, Marmara University, Istanbul, Turkey
| |
Collapse
|
34
|
van Hateren A, Bailey A, Elliott T. Recent advances in Major Histocompatibility Complex (MHC) class I antigen presentation: Plastic MHC molecules and TAPBPR-mediated quality control. F1000Res 2017; 6:158. [PMID: 28299193 PMCID: PMC5321123 DOI: 10.12688/f1000research.10474.1] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/13/2017] [Indexed: 01/25/2023] Open
Abstract
We have known since the late 1980s that the function of classical major histocompatibility complex (MHC) class I molecules is to bind peptides and display them at the cell surface to cytotoxic T cells. Recognition by these sentinels of the immune system can lead to the destruction of the presenting cell, thus protecting the host from pathogens and cancer. Classical MHC class I molecules (MHC I hereafter) are co-dominantly expressed, polygenic, and exceptionally polymorphic and have significant sequence diversity. Thus, in most species, there are many different MHC I allotypes expressed, each with different peptide-binding specificity, which can have a dramatic effect on disease outcome. Although MHC allotypes vary in their primary sequence, they share common tertiary and quaternary structures. Here, we review the evidence that, despite this commonality, polymorphic amino acid differences between allotypes alter the ability of MHC I molecules to change shape (that is, their conformational plasticity). We discuss how the peptide loading co-factor tapasin might modify this plasticity to augment peptide loading. Lastly, we consider recent findings concerning the functions of the non-classical MHC I molecule HLA-E as well as the tapasin-related protein TAPBPR (transporter associated with antigen presentation binding protein-related), which has been shown to act as a second quality-control stage in MHC I antigen presentation.
Collapse
Affiliation(s)
- Andy van Hateren
- Institute for Life Sciences and Cancer Sciences Unit, University of Southampton, Southampton, UK
| | - Alistair Bailey
- Institute for Life Sciences and Cancer Sciences Unit, University of Southampton, Southampton, UK
| | - Tim Elliott
- Institute for Life Sciences and Cancer Sciences Unit, University of Southampton, Southampton, UK
| |
Collapse
|
35
|
Liu WJ, Lan J, Liu K, Deng Y, Yao Y, Wu S, Chen H, Bao L, Zhang H, Zhao M, Wang Q, Han L, Chai Y, Qi J, Zhao J, Meng S, Qin C, Gao GF, Tan W. Protective T Cell Responses Featured by Concordant Recognition of Middle East Respiratory Syndrome Coronavirus-Derived CD8+ T Cell Epitopes and Host MHC. THE JOURNAL OF IMMUNOLOGY 2016; 198:873-882. [PMID: 27903740 DOI: 10.4049/jimmunol.1601542] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 11/06/2016] [Indexed: 12/20/2022]
Abstract
The coordinated recognition of virus-derived T cell epitopes and MHC molecules by T cells plays a pivotal role in cellular immunity-mediated virus clearance. It has been demonstrated that the conformation of MHC class I (MHC I) molecules can be adjusted by the presented peptide, which impacts T cell activation. However, it is still largely unknown whether the conformational shift of MHC I influences the protective effect of virus-specific T cells. In this study, utilizing the Middle East respiratory syndrome coronavirus-infected mouse model, we observed that through the unusual secondary anchor Ile5, a CD8+ T cell epitope drove the conformational fit of Trp73 on the α1 helix of murine MHC I H-2Kd In vitro renaturation and circular dichroism assays indicated that this shift of the structure did not influence the peptide/MHC I binding affinity. Nevertheless, the T cell recognition and the protective effect of the peptide diminished when we made an Ile to Ala mutation at position 5 of the original peptide. The molecular bases of the concordant recognition of T cell epitopes and host MHC-dependent protection were demonstrated through both crystal structure determination and tetramer staining using the peptide-MHC complex. Our results indicate a coordinated MHC I/peptide interaction mechanism and provide a beneficial reference for T cell-oriented vaccine development against emerging viruses such as Middle East respiratory syndrome coronavirus.
Collapse
Affiliation(s)
- William J Liu
- College of Laboratory Medicine and Life Sciences, Institute of Medical Virology, Wenzhou Medical University, Wenzhou 325035, China.,Key Laboratory of Medical Virology, Ministry of Health, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Jiaming Lan
- Key Laboratory of Medical Virology, Ministry of Health, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China.,Department of Pathogenic Biology, Hebei Medical University, Shijiazhuang 050017, China
| | - Kefang Liu
- College of Laboratory Medicine and Life Sciences, Institute of Medical Virology, Wenzhou Medical University, Wenzhou 325035, China.,Key Laboratory of Medical Virology, Ministry of Health, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Yao Deng
- Key Laboratory of Medical Virology, Ministry of Health, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Yanfeng Yao
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Beijing 100021, China
| | - Shaolian Wu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Hong Chen
- Key Laboratory of Medical Virology, Ministry of Health, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Lingling Bao
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Beijing 100021, China
| | - Haifeng Zhang
- College of Laboratory Medicine and Life Sciences, Institute of Medical Virology, Wenzhou Medical University, Wenzhou 325035, China
| | - Min Zhao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qihui Wang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Lingxia Han
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Yan Chai
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jianxun Qi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jincun Zhao
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China; and
| | - Songdong Meng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Chuan Qin
- Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Beijing 100021, China
| | - George F Gao
- College of Laboratory Medicine and Life Sciences, Institute of Medical Virology, Wenzhou Medical University, Wenzhou 325035, China; .,Key Laboratory of Medical Virology, Ministry of Health, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China.,CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.,Research Network of Immunity and Health, Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing 100101, China
| | - Wenjie Tan
- College of Laboratory Medicine and Life Sciences, Institute of Medical Virology, Wenzhou Medical University, Wenzhou 325035, China; .,Key Laboratory of Medical Virology, Ministry of Health, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| |
Collapse
|
36
|
García-Guerrero E, Pérez-Simón JA, Sánchez-Abarca LI, Díaz-Moreno I, De la Rosa MA, Díaz-Quintana A. The Dynamics of the Human Leukocyte Antigen Head Domain Modulates Its Recognition by the T-Cell Receptor. PLoS One 2016; 11:e0154219. [PMID: 27124285 PMCID: PMC4849770 DOI: 10.1371/journal.pone.0154219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 04/11/2016] [Indexed: 01/13/2023] Open
Abstract
Generating the immune response requires the discrimination of peptides presented by the human leukocyte antigen complex (HLA) through the T-cell receptor (TCR). However, how a single amino acid substitution in the antigen bonded to HLA affects the response of T cells remains uncertain. Hence, we used molecular dynamics computations to analyze the molecular interactions between peptides, HLA and TCR. We compared immunologically reactive complexes with non-reactive and weakly reactive complexes. MD trajectories were produced to simulate the behavior of isolated components of the various p-HLA-TCR complexes. Analysis of the fluctuations showed that p-HLA binding barely restrains TCR motions, and mainly affects the CDR3 loops. Conversely, inactive p-HLA complexes displayed significant drop in their dynamics when compared with its free versus ternary forms (p-HLA-TCR). In agreement, the free non-reactive p-HLA complexes showed a lower amount of salt bridges than the responsive ones. This resulted in differences between the electrostatic potentials of reactive and inactive p-HLA species and larger vibrational entropies in non-elicitor complexes. Analysis of the ternary p-HLA-TCR complexes also revealed a larger number of salt bridges in the responsive complexes. To summarize, our computations indicate that the affinity of each p-HLA complex towards TCR is intimately linked to both, the dynamics of its free species and its ability to form specific intermolecular salt-bridges in the ternary complexes. Of outstanding interest is the emerging concept of antigen reactivity involving its interplay with the HLA head sidechain dynamics by rearranging its salt-bridges.
Collapse
Affiliation(s)
- Estefanía García-Guerrero
- Instituto de Biomedicina de Sevilla (IBIS)/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - José Antonio Pérez-Simón
- Instituto de Biomedicina de Sevilla (IBIS)/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
- * E-mail: (ADQ); (JAPS)
| | | | - Irene Díaz-Moreno
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla—CSIC, Seville, Spain
| | - Miguel A. De la Rosa
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla—CSIC, Seville, Spain
| | - Antonio Díaz-Quintana
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla—CSIC, Seville, Spain
- * E-mail: (ADQ); (JAPS)
| |
Collapse
|
37
|
Differential utilization of binding loop flexibility in T cell receptor ligand selection and cross-reactivity. Sci Rep 2016; 6:25070. [PMID: 27118724 PMCID: PMC4846865 DOI: 10.1038/srep25070] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 04/11/2016] [Indexed: 12/27/2022] Open
Abstract
Complementarity determining region (CDR) loop flexibility has been suggested to play an important role in the selection and binding of ligands by T cell receptors (TCRs) of the cellular immune system. However, questions remain regarding the role of loop motion in TCR binding, and crystallographic structures have raised questions about the extent to which generalizations can be made. Here we studied the flexibility of two structurally well characterized αβ TCRs, A6 and DMF5. We found that the two receptors utilize loop motion very differently in ligand binding and cross-reactivity. While the loops of A6 move rapidly in an uncorrelated fashion, those of DMF5 are substantially less mobile. Accordingly, the mechanisms of binding and cross-reactivity are very different between the two TCRs: whereas A6 relies on conformational selection to select and bind different ligands, DMF5 uses a more rigid, permissive architecture with greater reliance on slower motions or induced-fit. In addition to binding site flexibility, we also explored whether ligand-binding resulted in common dynamical changes in A6 and DMF5 that could contribute to TCR triggering. Although binding-linked motional changes propagated throughout both receptors, no common features were observed, suggesting that changes in nanosecond-level TCR structural dynamics do not contribute to T cell signaling.
Collapse
|
38
|
Rashin AA, Jernigan RL. Clusters of Structurally Similar MHC I HLA-A2 Molecules, Found with a New Method, Suggest Mechanisms of T-Cell Receptor Avidity. Biochemistry 2016; 55:167-85. [PMID: 26600404 DOI: 10.1021/acs.biochem.5b01077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Only α1 and α2 domains of the α-chain of the major histocompatibility complex (MHC) directly bind peptide antigens (Ag-s) and the T-cell receptor (TCR). Significant plasticity was found in the TCR but only minor in (α1 + α2). The α3-domain position variation was noted only in connection to its binding the coreceptor CD8. We apply our methods for identifying functional conformational changes in proteins to a systematic study of similarities between 43 X-ray structures of the entire α chains of MHC-I HLA-A2. Out of 903 different αHLA-A2 pairs 203 show similarities within the earlier determined uncertainty threshold and unexpectedly form three similarity clusters (SCs) with all/most structures in a cluster similar within the uncertainty threshold. Pairs from different SCs always differ above the threshold, mainly due to variations in the α3 position/structure. All structures in SC3 cannot bind the CD8 coreceptor. Strong hydrogen bonds between (α1 + α2) and α3 differ between SC1 and SC2 but are nearly invariant within each SC. Small conformational changes in the (α1 + α2), caused by Ag-s differences, act as an α3 "allosteric switch" between SC2 and SC1. Binding of CD8 to SC2-HLA-A2 (Tax-type Ag-s) changes it to SC1-HLA-A2 (HuD-type Ag-s). HuD binding to HLA-A2 is much less stable than Tax binding. CD8-liganded HLA-A2 preference for binding HuD suggests that CD8-HLA-A2 may present a weakly binding peptide for TCR recognition, supporting the hypothesis that CD8 increases TCR avidity to weak Ag-s. Other HLA-A2 functions may involve α3. TCR-A6-liganded-Tax-type-HLA-A2s form two small clusters, similar to either A6-liganded-HuD or A6-liganded-native-Tax HLA-A2s.
Collapse
Affiliation(s)
- Alexander A Rashin
- BioChemComp Inc , 543 Sagamore Avenue, Teaneck, New Jersey 07666, United States
- LH Baker Center for Bioinformatics and Department of Biochemistry, Biophysics and Molecular Biology, 112 Office and Lab Building, Iowa State University , Ames, Iowa 50011-3020, United States
| | - Robert L Jernigan
- LH Baker Center for Bioinformatics and Department of Biochemistry, Biophysics and Molecular Biology, 112 Office and Lab Building, Iowa State University , Ames, Iowa 50011-3020, United States
| |
Collapse
|
39
|
Kozono H, Matsushita Y, Ogawa N, Kozono Y, Miyabe T, Sekiguchi H, Ichiyanagi K, Okimoto N, Taiji M, Kanagawa O, Sasaki YC. Single-molecule motions of MHC class II rely on bound peptides. Biophys J 2015; 108:350-9. [PMID: 25606683 DOI: 10.1016/j.bpj.2014.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 11/26/2014] [Accepted: 12/02/2014] [Indexed: 11/28/2022] Open
Abstract
The major histocompatibility complex (MHC) class II protein can bind peptides of different lengths in the region outside the peptide-binding groove. Peptide-flanking residues (PFRs) contribute to the binding affinity of the peptide for MHC and change the immunogenicity of the peptide/MHC complex with regard to T cell receptor (TCR). The mechanisms underlying these phenomena are currently unknown. The molecular flexibility of the peptide/MHC complex may be an important determinant of the structures recognized by certain T cells. We used single-molecule x-ray analysis (diffracted x-ray tracking (DXT)) and fluorescence anisotropy to investigate these mechanisms. DXT enabled us to monitor the real-time Brownian motion of the peptide/MHC complex and revealed that peptides without PFRs undergo larger rotational motions than peptides with PFRs. Fluorescence anisotropy further revealed that peptides without PFRs exhibit slightly larger motions on the nanosecond timescale. These results demonstrate that peptides without PFRs undergo dynamic motions in the groove of MHC and consequently are able to assume diverse structures that can be recognized by T cells.
Collapse
Affiliation(s)
- Haruo Kozono
- CREST Sasaki Team, Japan Science and Technology Agency, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan; Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan.
| | - Yufuku Matsushita
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Naoki Ogawa
- CREST Sasaki Team, Japan Science and Technology Agency, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan; Graduate School for Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Yuko Kozono
- Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan
| | - Toshihiro Miyabe
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Hiroshi Sekiguchi
- CREST Sasaki Team, Japan Science and Technology Agency, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan; Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Kouhei Ichiyanagi
- CREST Sasaki Team, Japan Science and Technology Agency, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan; Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Noriaki Okimoto
- Computational Biology Research Core, Quantitative Biology Center, RIKEN, Hyogo, Japan
| | - Makoto Taiji
- Computational Biology Research Core, Quantitative Biology Center, RIKEN, Hyogo, Japan
| | - Osami Kanagawa
- CREST Sasaki Team, Japan Science and Technology Agency, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan; Centre International de Recherche en Infectiologie, INSERM U1111, Lyon, France
| | - Yuji C Sasaki
- CREST Sasaki Team, Japan Science and Technology Agency, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan; Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan.
| |
Collapse
|
40
|
Affiliation(s)
- Gregory
F. Pirrone
- Department of Chemistry and
Chemical Biology, Northeastern University, 360 Huntington Ave., Boston, Massachusetts 02115 United States
| | - Roxana E. Iacob
- Department of Chemistry and
Chemical Biology, Northeastern University, 360 Huntington Ave., Boston, Massachusetts 02115 United States
| | - John R. Engen
- Department of Chemistry and
Chemical Biology, Northeastern University, 360 Huntington Ave., Boston, Massachusetts 02115 United States
| |
Collapse
|
41
|
Sarkar R, Maji K, Haldar D. An efficient one pot ipso-nitration: structural transformation of a dipeptide by N-terminus modification. RSC Adv 2015. [DOI: 10.1039/c5ra09789d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
CuSO4 catalyzed one pot ipso-nitration of rigid dipeptide leads to structural transformation from anti parallel to parallel β-sheet.
Collapse
Affiliation(s)
- Rajib Sarkar
- Department
- of Chemical Sciences
- Indian Institute of Science Education and Research Kolkata
- India
| | - Krishnendu Maji
- Department
- of Chemical Sciences
- Indian Institute of Science Education and Research Kolkata
- India
| | - Debasish Haldar
- Department
- of Chemical Sciences
- Indian Institute of Science Education and Research Kolkata
- India
| |
Collapse
|
42
|
Understanding the structural dynamics of TCR-pMHC interactions. Trends Immunol 2014; 35:604-612. [DOI: 10.1016/j.it.2014.10.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 10/20/2014] [Accepted: 10/20/2014] [Indexed: 12/23/2022]
|
43
|
Hawse WF, Morel PA. An immunology primer for computational modelers. J Pharmacokinet Pharmacodyn 2014; 41:389-99. [PMID: 25238901 DOI: 10.1007/s10928-014-9384-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 09/09/2014] [Indexed: 11/30/2022]
Abstract
The immune system is designed to protect an organism from infection and damage caused by a pathogen. A successful immune response requires the coordinated function of multiple cell types and molecules in the innate and adaptive immune systems. Given the complexity of the immune system, it would be advantageous to build computational models to better understand immune responses and develop models to better guide the design of immunotherapies. Often, researchers with strong quantitative backgrounds do not have formal training in immunology. Therefore, the goal of this review article is to provide a brief primer on cellular immunology that is geared for computational modelers.
Collapse
Affiliation(s)
- William F Hawse
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA, USA,
| | | |
Collapse
|
44
|
Yanaka S, Ueno T, Shi Y, Qi J, Gao GF, Tsumoto K, Sugase K. Peptide-dependent conformational fluctuation determines the stability of the human leukocyte antigen class I complex. J Biol Chem 2014; 289:24680-90. [PMID: 25028510 DOI: 10.1074/jbc.m114.566174] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In immune-mediated control of pathogens, human leukocyte antigen (HLA) class I presents various antigenic peptides to CD8(+) T-cells. Long-lived peptide presentation is important for efficient antigen-specific T-cell activation. Presentation time depends on the peptide sequence and the stability of the peptide-HLA complex (pHLA). However, the determinant of peptide-dependent pHLA stability remains elusive. Here, to reveal the pHLA stabilization mechanism, we examined the crystal structures of an HLA class I allomorph in complex with HIV-derived peptides and evaluated site-specific conformational fluctuations using NMR. Although the crystal structures of various pHLAs were almost identical independent of the peptides, fluctuation analyses identified a peptide-dependent minor state that would be more tightly packed toward the peptide. The minor population correlated well with the thermostability and cell surface presentation of pHLA, indicating that this newly identified minor state is important for stabilizing the pHLA and facilitating T-cell recognition.
Collapse
Affiliation(s)
- Saeko Yanaka
- From the Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo 277-8562, Japan
| | - Takamasa Ueno
- Center for AIDS Research, Kumamoto University, Kumamoto 860-0811, Japan, International Research Center for Medical Sciences (IRCMS), Kumamoto University, Kumamoto 860-0811, Japan
| | - Yi Shi
- Research Network of Immunity and Health, Beijing Institute of Life Science, Chinese Academy of Sciences, Beijing 100101, China, CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jianxun Qi
- Research Network of Immunity and Health, Beijing Institute of Life Science, Chinese Academy of Sciences, Beijing 100101, China, CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - George F Gao
- Research Network of Immunity and Health, Beijing Institute of Life Science, Chinese Academy of Sciences, Beijing 100101, China, CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Kouhei Tsumoto
- From the Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo 277-8562, Japan, Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, Tokyo 108-8693, Japan, Medical Proteomics Laboratory, Institute of Medical Science, The University of Tokyo, Tokyo 108-8693, Japan, and
| | - Kenji Sugase
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Osaka 618-8503, Japan
| |
Collapse
|