1
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Hu R, Rodrigues JV, Pradeep Waduge J, Yamazaki H, Cressiot B, Chishti Y, Makowski L, Yu D, Shakhnovich E, Zhao Q, Wanunu M. Differential Enzyme Flexibility Probed Using Solid-State Nanopores. ACS Nano 2018; 12:4494-4502. [PMID: 29630824 PMCID: PMC9016714 DOI: 10.1021/acsnano.8b00734] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Enzymes and motor proteins are dynamic macromolecules that coexist in a number of conformations of similar energies. Protein function is usually accompanied by a change in structure and flexibility, often induced upon binding to ligands. However, while measuring protein flexibility changes between active and resting states is of therapeutic significance, it remains a challenge. Recently, our group has demonstrated that breadth of signal amplitudes in measured electrical signatures as an ensemble of individual protein molecules is driven through solid-state nanopores and correlates with protein conformational dynamics. Here, we extend our study to resolve subtle flexibility variation in dihydrofolate reductase mutants from unlabeled single molecules in solution. We first demonstrate using a canonical protein system, adenylate kinase, that both size and flexibility changes can be observed upon binding to a substrate that locks the protein in a closed conformation. Next, we investigate the influence of voltage bias and pore geometry on the measured electrical pulse statistics during protein transport. Finally, using the optimal experimental conditions, we systematically study a series of wild-type and mutant dihydrofolate reductase proteins, finding a good correlation between nanopore-measured protein conformational dynamics and equilibrium bulk fluorescence probe measurements. Our results unequivocally demonstrate that nanopore-based measurements reliably probe conformational diversity in native protein ensembles.
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Affiliation(s)
- Rui Hu
- State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, People’s Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, People’s Republic of China
| | - João V. Rodrigues
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - J Pradeep Waduge
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, United States
| | - Hirohito Yamazaki
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, United States
| | - Benjamin Cressiot
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, United States
| | - Yasmin Chishti
- Department of Bioengineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Lee Makowski
- Department of Bioengineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Dapeng Yu
- State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, People’s Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, People’s Republic of China
| | - Eugene Shakhnovich
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Qing Zhao
- State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, People’s Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, People’s Republic of China
- Corresponding Authors:.,
| | - Meni Wanunu
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, United States
- Corresponding Authors:.,
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2
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Onuk E, Badger J, Wang YJ, Bardhan J, Chishti Y, Akcakaya M, Brooks DH, Erdogmus D, Minh DDL, Makowski L. Effects of Catalytic Action and Ligand Binding on Conformational Ensembles of Adenylate Kinase. Biochemistry 2017; 56:4559-4567. [PMID: 28767234 DOI: 10.1021/acs.biochem.7b00351] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Crystal structures of adenylate kinase (AdK) from Escherichia coli capture two states: an "open" conformation (apo) obtained in the absence of ligands and a "closed" conformation in which ligands are bound. Other AdK crystal structures suggest intermediate conformations that may lie on the transition pathway between these two states. To characterize the transition from open to closed states in solution, X-ray solution scattering data were collected from AdK in the apo form and with progressively increasing concentrations of five different ligands. Scattering data from apo AdK are consistent with scattering predicted from the crystal structure of AdK in the open conformation. In contrast, data from AdK samples saturated with Ap5A do not agree with that calculated from AdK in the closed conformation. Using cluster analysis of available structures, we selected representative structures in five conformational states: open, partially open, intermediate, partially closed, and closed. We used these structures to estimate the relative abundances of these states for each experimental condition. X-ray solution scattering data obtained from AdK with AMP are dominated by scattering from AdK in the open conformation. For AdK in the presence of high concentrations of ATP and ADP, the conformational ensemble shifts to a mixture of partially open and closed states. Even when AdK is saturated with Ap5A, a significant proportion of AdK remains in a partially open conformation. These results are consistent with an induced-fit model in which the transition of AdK from an open state to a closed state is initiated by ATP binding.
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Affiliation(s)
- Emre Onuk
- Radiation Oncology Department, University of California , Los Angeles, California 90095, United States
| | - John Badger
- DeltaG Technologies , San Diego, California 92122, United States
| | - Yu Jing Wang
- Department of Bioengineering, Northeastern University , Boston, Massachusetts 02115, United States
| | - Jaydeep Bardhan
- Department of Mechanical and Industrial Engineering, Northeastern University , Boston, Massachusetts 02115, United States
| | - Yasmin Chishti
- Department of Bioengineering, Northeastern University , Boston, Massachusetts 02115, United States
| | - Murat Akcakaya
- Department of Electrical and Computer Engineering, University of Pittsburgh , Pittsburgh, Pennsylvania 15261, United States
| | - Dana H Brooks
- Department of Electrical and Computer Engineering, Northeastern University , Boston, Massachusetts 02115, United States
| | - Deniz Erdogmus
- Department of Electrical and Computer Engineering, Northeastern University , Boston, Massachusetts 02115, United States
| | - David D L Minh
- Department of Chemistry, Illinois Institute of Technology , Chicago, Illinois 60616, United States
| | - Lee Makowski
- Department of Bioengineering, Northeastern University , Boston, Massachusetts 02115, United States.,Department of Chemistry and Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States
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3
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Abstract
All living systems depend on metalloproteins. Yet, while tools for the separation and identification of apo-proteins are well developed, those enabling identification and quantitation of individual metalloproteins within complex mixtures are still nascent. Here, we describe the electrophoretic separation of a mixture of carbonic anhydrase, ceruloplasmin, urease, and hemoglobin using native 2D gel electrophoresis and X-ray fluorescence mapping-an approach we have developed to be broadly applicable, not require specialized equipment for sample preparation, and likely to be extensible in the future.
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Affiliation(s)
- Tripti Khare
- Biosciences Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL, USA
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4
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Wolford JL, Chishti Y, Jin Q, Ward J, Chen L, Vogt S, Finney L. Loss of pluripotency in human embryonic stem cells directly correlates with an increase in nuclear zinc. PLoS One 2010; 5:e12308. [PMID: 20808840 PMCID: PMC2924898 DOI: 10.1371/journal.pone.0012308] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Accepted: 07/21/2010] [Indexed: 01/02/2023] Open
Abstract
The pluripotency of human embryonic stem cells (hESCs) is important to investigations of early development and to cell replacement therapy, but the mechanism behind pluripotency is incompletely understood. Zinc has been shown to play a key role in differentiation of non-pluripotent cell types, but here its role in hESCs is directly examined. By mapping the distribution of metals in hESCs at high resolution by x-ray fluorescence microprobe (XFM) and by analyzing subcellular metal content, we have found evidence that loss of pluripotency is directly correlated with an increase in nuclear zinc. Zinc elevation not only redefines our understanding of the mechanisms that support pluripotency, but also may act as a biomarker and an intervention point for stem cell differentiation.
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Affiliation(s)
- Janet L. Wolford
- Biosciences Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, United States of America
| | - Yasmin Chishti
- Biosciences Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, United States of America
| | - Qiaoling Jin
- Biosciences Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, United States of America
| | - Jesse Ward
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, United States of America
| | - Liaohai Chen
- Biosciences Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, United States of America
| | - Stefan Vogt
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, United States of America
| | - Lydia Finney
- Biosciences Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, United States of America
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, United States of America
- * E-mail:
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5
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Finney L, Chishti Y, Khare T, Giometti C, Levina A, Lay PA, Vogt S. Imaging metals in proteins by combining electrophoresis with rapid x-ray fluorescence mapping. ACS Chem Biol 2010; 5:577-87. [PMID: 20392082 DOI: 10.1021/cb1000263] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Growing evidence points toward a very dynamic role for metals in biology. This suggests that physiological circumstance may mandate metal ion redistribution among ligands. This work addresses a critical need for technology that detects, identifies, and measures the metal-containing components of complex biological matrixes. We describe a direct, user-friendly approach for identifying and quantifying metal-protein adducts in complex samples using native- or SDS-PAGE, blotting, and rapid synchrotron X-ray fluorescence mapping with micro-XANES (X-ray absorption near-edge structure) of entire blots. The identification and quantification of each metal bound to a protein spot has been demonstrated, and the technique has been applied in two exemplary cases. In the first, the speciation of the in vitro binding of exogenous chromium to blood serum proteins was influenced markedly by both the oxidation state of chromium exposed to the serum proteins and the treatment conditions, which is of relevance to the biochemistry of Cr dietary supplements. In the second case, in vivo changes in endogenous metal speciation were examined to probe the influence of oxygen depletion on iron speciation in Shewanella oneidensis.
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Affiliation(s)
- Lydia Finney
- Biosciences Division and
- X-ray Sciences Division, Argonne National Laboratory, Argonne, Illinois
| | | | | | | | - Aviva Levina
- School of Chemistry, The University of Sydney, NSW 2006, Australia
| | - Peter A Lay
- School of Chemistry, The University of Sydney, NSW 2006, Australia
| | - Stefan Vogt
- X-ray Sciences Division, Argonne National Laboratory, Argonne, Illinois
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6
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Finney L, Wolford J, Jin Q, Chishti Y, Ward J, Vogt S, Chen L. ELEMENTAL IMAGING OF HUMAN EMBRYONIC STEM CELLS. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.lb214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Janet Wolford
- Biosciences DivisionArgonne National LaboratoryLemontIL
| | - Qiaoling Jin
- Biosciences DivisionArgonne National LaboratoryLemontIL
| | | | - Jesse Ward
- X‐ray Science Division, Advanced Photon SourceArgonne National LaboratoryLemontIL
| | - Stefan Vogt
- X‐ray Science Division, Advanced Photon SourceArgonne National LaboratoryLemontIL
| | - Liaohai Chen
- Biosciences DivisionArgonne National LaboratoryLemontIL
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7
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Mouffouk F, Chishti Y, Jin Q, Rosa ME, Rivera M, Dasa S, Chen L. Polymeric micelle-based bioassay with femtomolar sensitivity. Anal Biochem 2008; 372:140-7. [PMID: 18005929 PMCID: PMC2759188 DOI: 10.1016/j.ab.2007.09.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Revised: 09/10/2007] [Accepted: 09/17/2007] [Indexed: 11/28/2022]
Abstract
Target-specific polymeric micelles loaded with fluorescence dye molecules in their hydrophobic cores were made from block copolymer of poly(caprolactones)23-b-poly(ethylene oxide)45. It was found that the micelles are stable against pH changes from pH 2 to 12 and temperature variation up to 65 degrees C. The dye molecules can be released to the solution on exposing the micelles to organic solvents or ultrasound. A rapid and highly sensitive immunoassay based on the above micelles was developed, and the assay can detect specific target proteins in the femtomolar range from complex biological samples such as serum mimics and cell lysate. For example, less than 0.15 U/ml of ovarian cancer-specific antigen 125, equivalent to 7.5 x 10(-15)M, can be reliably detected in solution. We also demonstrated that the assay can detect a cell surface biomarker, stage-specific embryonic antigen 4, from a single human embryonic stem cell.
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Affiliation(s)
- Fouzi Mouffouk
- Department of Obstetrics & Gynecology, Rush University Medical Center Chicago IL 60612 USA
- Biosciences Division, Argonne National Laboratory, Argonne, IL, 60439
| | - Yasmin Chishti
- Biosciences Division, Argonne National Laboratory, Argonne, IL, 60439
| | - Qiaoling Jin
- Biosciences Division, Argonne National Laboratory, Argonne, IL, 60439
| | | | - Melixa Rivera
- University of Puerto Rico at Mayaguez, Mayaguez, PR 00680
| | - Siva Dasa
- Department of Obstetrics & Gynecology, Rush University Medical Center Chicago IL 60612 USA
| | - Liaohai Chen
- Department of Obstetrics & Gynecology, Rush University Medical Center Chicago IL 60612 USA
- Biosciences Division, Argonne National Laboratory, Argonne, IL, 60439
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8
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Kim M, Yang H, Kim SK, Reche PA, Tirabassi RS, Hussey RE, Chishti Y, Rheinwald JG, Morehead TJ, Zech T, Damon IK, Welsh RM, Reinherz EL. Biochemical and functional analysis of smallpox growth factor (SPGF) and anti-SPGF monoclonal antibodies. J Biol Chem 2004; 279:25838-48. [PMID: 15070899 DOI: 10.1074/jbc.m400343200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Variola, the causative agent of smallpox, is a highly infectious double-stranded DNA virus of the orthopox genus that replicates within the cytoplasm of infected cells. For unknown reasons prominent skin manifestations, including "pox," mark the course of this systemic human disease. Here we characterized smallpox growth factor (SPGF), a protein containing an epidermal growth factor (EGF)-like domain that is conserved among orthopox viral genomes, and investigated its possible mechanistic link. We show that after recombinant expression, refolding, and purification, the EGF domain of SPGF binds exclusively to the broadly expressed cellular receptor, erb-B1 (EGF receptor), with subnanomolar affinity, stimulating the growth of primary human keratinocytes and fibroblasts. High affinity monoclonal antibodies specific for SPGF reveal in vivo immunoprotection in a murine vaccinia pneumonia model by a mechanism distinct from viral neutralization. These findings suggest that blockade of pathogenic factor actions, in general, may be advantageous to the infected host.
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Affiliation(s)
- Mikyung Kim
- Department of Medical Oncology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA
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9
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Kim M, Chen B, Hussey RE, Chishti Y, Montefiori D, Hoxie JA, Byron O, Campbell G, Harrison SC, Reinherz EL. The stoichiometry of trimeric SIV glycoprotein interaction with CD4 differs from that of anti-envelope antibody Fab fragments. J Biol Chem 2001; 276:42667-76. [PMID: 11544255 DOI: 10.1074/jbc.m104166200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Human and simian immunodeficiency viruses infect host lymphoid cells by binding CD4 molecules via their gp160 envelope glycoproteins. Biochemical studies on recombinant SIVmac32H (pJ5) envelope ectodomain gp140 precursor protein show that the envelope is a trimer. Using size exclusion chromatography, quantitative amino acid analysis, analytical ultracentrifugation, and CD4-based competition assay, we demonstrate that the stoichiometry of CD4 receptor-oligomeric envelope interaction is 1:1. By contrast, Fab fragments of both neutralizing and non-neutralizing monoclonal antibodies bind at a 3:1 ratio. Thus, despite displaying equivalent CD4 binding sites on each of the three gp140 protomers within an uncleaved trimer, only one site binds the soluble 4-domain human CD4 extracellular segment. The anti-cooperativity and the faster k(off) of gp140 trimer:CD4 versus gp120 monomer:CD4 interaction suggest that CD4-induced conformational change is impeded in the intact envelope. The implications of these findings for immunity against human immunodeficiency virus and simian immunodeficiency virus are discussed.
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Affiliation(s)
- M Kim
- Laboratory of Immunobiology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA
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10
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Zhang CW, Chishti Y, Hussey RE, Reinherz EL. Expression, purification, and characterization of recombinant HIV gp140. The gp41 ectodomain of HIV or simian immunodeficiency virus is sufficient to maintain the retroviral envelope glycoprotein as a trimer. J Biol Chem 2001; 276:39577-85. [PMID: 11514580 DOI: 10.1074/jbc.m107147200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Efforts to understand the molecular basis of human immunodeficiency virus (HIV) envelope glycoprotein function have been hampered by the inability to generate sufficient quantities of homogeneous material. We now report on the high level expression, purification, and characterization of soluble HIV gp140 ectodomain proteins in Chinese hamster ovary-Lec3.2.8.1 cells. Gel filtration and analytical ultracentrifugation show that the uncleaved ADA strain-derived gp140 proteins are trimeric without further modification required to maintain oligomers. These spike proteins are native as judged by soluble CD4 (sCD4) (K(D) = 1-2 nm) and monoclonal antibody binding studies using surface plasmon resonance. CD4 ligation induces conformational change in the trimer, exposing the chemokine receptor binding site as assessed by 17b monoclonal antibody reactivity. Lack of anti-cooperativity in sCD4-ADA trimer interaction distinct from that observed with sCD4-SIV mac32H implies quaternary structural differences in ground states of their respective spike proteins.
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Affiliation(s)
- C W Zhang
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, 44 Binney Street, Boston, MA 02115, USA
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11
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Chen B, Zhou G, Kim M, Chishti Y, Hussey RE, Ely B, Skehel JJ, Reinherz EL, Harrison SC, Wiley DC. Expression, purification, and characterization of gp160e, the soluble, trimeric ectodomain of the simian immunodeficiency virus envelope glycoprotein, gp160. J Biol Chem 2000; 275:34946-53. [PMID: 10944528 DOI: 10.1074/jbc.m004905200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The envelope glycoprotein, gp160, of simian immunodeficiency virus (SIV) shares approximately 25% sequence identity with gp160 from the human immunodeficiency virus, type I, indicating a close structural similarity. As a result of binding to cell surface CD4 and co-receptor (e.g. CCR5 and CXCR4), both SIV and human immunodeficiency virus gp160 mediate viral entry by membrane fusion. We report here the characterization of gp160e, the soluble ectodomain of SIV gp160. The ectodomain has been expressed in both insect cells and Chinese hamster ovary (CHO)-Lec3.2.8.1 cells, deficient in enzymes necessary for synthesizing complex oligosaccharides. Both the primary and a secondary proteolytic cleavage sites between the gp120 and gp41 subunits of gp160 were mutated to prevent cleavage and shedding of gp120. The purified, soluble glycoprotein is shown to be trimeric by chemical cross-linking, gel filtration chromatography, and analytical ultracentrifugation. It forms soluble, tight complexes with soluble CD4 and a number of Fab fragments from neutralizing monoclonal antibodies. Soluble complexes were also produced of enzymatically deglycosylated gp160e and of gp160e variants with deletions in the variable segments.
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MESH Headings
- Animals
- Antibodies, Monoclonal/metabolism
- CD4 Antigens/metabolism
- CHO Cells
- Cell Line
- Chromatography, Gel
- Circular Dichroism
- Cricetinae
- Cross-Linking Reagents
- Electrophoresis, Polyacrylamide Gel
- Gene Deletion
- Gene Products, env/chemistry
- Gene Products, env/genetics
- Gene Products, env/isolation & purification
- Gene Products, env/metabolism
- Glycosylation
- Insecta
- Models, Genetic
- Mutagenesis, Site-Directed
- Protein Binding
- Protein Structure, Tertiary
- Ultracentrifugation
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Affiliation(s)
- B Chen
- Laboratory of Molecular Medicine, The Children's Hospital, Howard Hughes Medical Institute, Boston, Massachusetts 02215, USA
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12
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Wang J, Lim K, Smolyar A, Teng M, Liu J, Tse AG, Liu J, Hussey RE, Chishti Y, Thomson CT, Sweet RM, Nathenson SG, Chang HC, Sacchettini JC, Reinherz EL. Atomic structure of an alphabeta T cell receptor (TCR) heterodimer in complex with an anti-TCR fab fragment derived from a mitogenic antibody. EMBO J 1998; 17:10-26. [PMID: 9427737 PMCID: PMC1170354 DOI: 10.1093/emboj/17.1.10] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Each T cell receptor (TCR) recognizes a peptide antigen bound to a major histocompatibility complex (MHC) molecule via a clonotypic alphabeta heterodimeric structure (Ti) non-covalently associated with the monomorphic CD3 signaling components. A crystal structure of an alphabeta TCR-anti-TCR Fab complex shows an Fab fragment derived from the H57 monoclonal antibody (mAb), interacting with the elongated FG loop of the Cbeta domain, situated beneath the Vbeta domain. This loop, along with the partially exposed ABED beta sheet of Cbeta, and glycans attached to both Cbeta and Calpha domains, forms a cavity of sufficient size to accommodate a single non-glycosylated Ig domain such as the CD3epsilon ectodomain. That this asymmetrically localized site is embedded within the rigid constant domain module has implications for the mechanism of signal transduction in both TCR and pre-TCR complexes. Furthermore, quaternary structures of TCRs vary significantly even when they bind the same MHC molecule, as manifested by a unique twisting of the V module relative to the C module.
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Affiliation(s)
- J Wang
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
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13
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Liu J, Tse AG, Chang HC, Liu JH, Wang J, Hussey RE, Chishti Y, Rheinhold B, Spoerl R, Nathenson SG, Sacchettini JC, Reinherz EL. Crystallization of a deglycosylated T cell receptor (TCR) complexed with an anti-TCR Fab fragment. J Biol Chem 1996; 271:33639-46. [PMID: 8969233 DOI: 10.1074/jbc.271.52.33639] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
A strategy to overexpress T cell receptors (TCRs) in Lec3.2.8.1 cells has been developed using the "Velcro" leucine zipper sequence to facilitate alpha-beta pairing. Upon secretion in culture media, the VSV-8-specific/H2-Kb-restricted N15 TCR could be readily immunopurified using the anti-leucine zipper monoclonal antibody 2H11, with a yield of 5-10 mg/liter. Mass spectrometry analysis revealed that all attached glycans were GlcNAc2-Man5. Following Superdex 200 gel filtration to remove aggregates, wild-type N15 or N15(s), a C183S variant lacking the unpaired cysteine at amino acid residue 183 in the Cbeta domain, was thrombin-cleaved and endoglycosidase H-digested, and the two derivatives were termed iN15DeltaH and N15(s)DeltaH, respectively, and sized by Superdex 75 chromatography to high purity. N-terminal and C-terminal microsequencing analysis showed the expected unique termini of N15 alpha and beta subunits. Nevertheless, neither protein crystallized under a wide range of conditions. Subsequently, we produced a Fab fragment of the murine TCR Cbeta-specific hamster monoclonal antibody H57 and complexed the Fab fragment with iN15DeltaH and N15(s)DeltaH. Both N15(s)DeltaH-Fab[H57] and iN15DeltaH-Fab[H57] complexes crystallize, with the former diffracting to 2.8-A resolution. These findings show that neither intact glycans nor the conserved and partially exposed Cys-183 is required for protein stability. Furthermore, our results suggest that the H57 Fab fragment aids in the crystallization of TCRs by altering their molecular surface and/or stabilizing inherent conformational mobility.
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Affiliation(s)
- J Liu
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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