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Feng H, Shen H, Robeson MJ, Wu YH, Wu HK, Chen GJ, Zhang S, Xie P, Jin L, He Y, Wang Y, Lv F, Hu X, Zhang Y, Xiao RP. MG53 E3 Ligase-Dead Mutant Protects Diabetic Hearts From Acute Ischemic/Reperfusion Injury and Ameliorates Diet-Induced Cardiometabolic Damage. Diabetes 2022; 71:298-314. [PMID: 34844991 PMCID: PMC8914286 DOI: 10.2337/db21-0322] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 11/14/2021] [Indexed: 01/08/2023]
Abstract
Cardiometabolic diseases, including diabetes and its cardiovascular complications, are the global leading causes of death, highlighting a major unmet medical need. Over the past decade, mitsugumin 53 (MG53), also called TRIM72, has emerged as a powerful agent for myocardial membrane repair and cardioprotection, but its therapeutic value is complicated by its E3 ligase activity, which mediates metabolic disorders. Here, we show that an E3 ligase-dead mutant, MG53-C14A, retains its cardioprotective function without causing metabolic adverse effects. When administered in normal animals, both the recombinant human wild-type MG53 protein (rhMG53-WT) and its E3 ligase-dead mutant (rhMG53-C14A) protected the heart equally from myocardial infarction and ischemia/reperfusion (I/R) injury. However, in diabetic db/db mice, rhMG53-WT treatment markedly aggravated hyperglycemia, cardiac I/R injury, and mortality, whereas acute and chronic treatment with rhMG53-C14A still effectively ameliorated I/R-induced myocardial injury and mortality or diabetic cardiomyopathy, respectively, without metabolic adverse effects. Furthermore, knock-in of MG53-C14A protected the mice from high-fat diet-induced metabolic disorders and cardiac damage. Thus, the E3 ligase-dead mutant MG53-C14A not only protects the heart from acute myocardial injury but also counteracts metabolic stress, providing a potentially important therapy for the treatment of acute myocardial injury in metabolic disorders, including diabetes and obesity.
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Affiliation(s)
- Han Feng
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Hao Shen
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Matthew J. Robeson
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA
| | - Yue-Han Wu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Hong-Kun Wu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Geng-Jia Chen
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Shuo Zhang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Peng Xie
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Li Jin
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Yanyun He
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Yingfan Wang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Fengxiang Lv
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Xinli Hu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
- Beijing City Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing, China
| | - Yan Zhang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
- Key Laboratory of Molecular Cardiovascular Sciences, Institute of Cardiovascular Sciences, Ministry of Education, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
- Corresponding authors: Rui-Ping Xiao, , and Yan Zhang,
| | - Rui-Ping Xiao
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
- Beijing City Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
- Peking University–Nanjing Joint Institute of Translational Medicine, Nanjing, China
- Corresponding authors: Rui-Ping Xiao, , and Yan Zhang,
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Chang YC, Kao CY, Tang HC, Huang MS, Mou KY. Direct Antibody Isolation on Cells Using Affinity-Tag-Guided Proximity Selection. Biochemistry 2020; 59:4285-4293. [DOI: 10.1021/acs.biochem.0c00730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- You-Chiun Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Chia-Yi Kao
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei 11529, Taiwan
| | - Hao-Cheng Tang
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Meng-Sen Huang
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
| | - Kurt Yun Mou
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
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Mehdipour T, Tohidkia MR, Ata Saei A, Kazemi A, Khajeh S, Rahim Rahimi AA, Nikfarjam S, Farhadi M, Halimi M, Soleimani R, Zubarev RA, Nouri M. Tailoring subtractive cell biopanning to identify diffuse gastric adenocarcinoma-associated antigens via human scFv antibodies. Immunology 2019; 159:96-108. [PMID: 31596953 DOI: 10.1111/imm.13129] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 09/27/2019] [Accepted: 10/03/2019] [Indexed: 12/24/2022] Open
Abstract
Among various solid tumours, gastric cancer (GC) is one of the leading causes of cancer-related deaths worldwide. Expansion into the peritoneal cavity, which results from dissemination of diffuse cancer cells, is the main cause of mortality in gastric adenocarcinoma patients. Therefore, investigation of putative biomarkers involved in metastasis is prerequisite for GC management. In an effort to discover potential tumour markers associated with peritoneal metastasis of GC, a semi-synthetic human scFv library (Tomlinson I) was used to isolate novel antibody fragments recognizing MKN-45, a poorly differentiated diffuse gastric adenocarcinoma cell line. Four rounds of subtractive selection each consisting of extensive pre-absorption of phage library with NIH-3T3 murine embryonic fibroblasts and AGS (a well-differentiated intestinal gastric adenocarcinoma) cell line were carried out prior to positive selection on MKN-45 target cells. ELISA-based screening of 192 phage-displayed scFv clones indicated 21 high-affinity binders with specific staining of MKN-45 compared with AGS cells. Diversity analysis of the selected phage-scFvs resulted in five distinct sequences with multiple frequency. Further analysis by ELISA and flow cytometry verified three clones that specifically recognized MKN-45 cells. Liquid chromatography-mass spectrometry analysis of the scFv-immunoprecipitated proteins has led to identification of c-Met, HSP90 α and HSP90 β as candidate biomarkers associated with diffuse GC. Immunohistochemistry revealed the capability of purified scFvs to differentiate diffuse and intestinal gastric adenocarcinoma. Taken together, the isolated MKN-45-specific scFv fragments and their cognate antigens would be beneficial in screening and management as well as targeting and therapy of the diffuse gastric adenocarcinoma.
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Affiliation(s)
- Tayebeh Mehdipour
- Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Medical Biotechnology, School of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad R Tohidkia
- Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Amir Ata Saei
- Division of Physiological Chemistry I, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Amir Kazemi
- Department of Microbiology, Islamic Azad University, Shahr-e-Qods Branch, Tehran, Iran
| | - Shirin Khajeh
- Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ali A Rahim Rahimi
- Department of Microbiology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Sepideh Nikfarjam
- Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mehrdad Farhadi
- Department of Pathology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Monireh Halimi
- Department of Pathology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ramin Soleimani
- Department of Molecular Biology, Research and Diagnostic Laboratory of Dook, Sari, Iran
| | - Roman A Zubarev
- Division of Physiological Chemistry I, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden.,Department of Pharmacological & Technological Chemistry, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Mohammad Nouri
- Department of Medical Biotechnology, School of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
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Ligandomics: a paradigm shift in biological drug discovery. Drug Discov Today 2018; 23:636-643. [PMID: 29326083 DOI: 10.1016/j.drudis.2018.01.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/10/2017] [Accepted: 01/04/2018] [Indexed: 02/06/2023]
Abstract
As productivity of pharmaceutical research and development (R&D) for small-molecule drugs declines, the trend in drug discovery strategies is shifting towards biologics, which predominantly target secreted or cell surface proteins. Receptors and ligands are the most-valuable drug targets. In contrast to conventional approaches of discovering one ligand at a time, the emerging technology of ligandomics can systematically map disease-selective cellular ligands in the absence of molecular probes. Biologics targeting these ligands with disease selectivity have the advantages of high efficacy, minimal adverse effects, wide therapeutic indices, and low safety-related attrition rates. Therefore, ligandomics represents a paradigm shift to address the bottleneck of target discovery for biologics development.
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Huang R, Kiss MM, Batonick M, Weiner MP, Kay BK. Generating Recombinant Antibodies to Membrane Proteins through Phage Display. Antibodies (Basel) 2016; 5:antib5020011. [PMID: 31557992 PMCID: PMC6698964 DOI: 10.3390/antib5020011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 04/21/2016] [Accepted: 04/21/2016] [Indexed: 01/03/2023] Open
Abstract
One of the most important classes of proteins in terms of drug targets is cell surface membrane proteins, and yet it is a challenging set of proteins for generating high-quality affinity reagents. In this review, we focus on the use of phage libraries, which display antibody fragments, for generating recombinant antibodies to membrane proteins. Such affinity reagents generally have high specificity and affinity for their targets. They have been used for cell staining, for promoting protein crystallization to solve three-dimensional structures, for diagnostics, and for treating diseases as therapeutics. We cover publications on this topic from the past 10 years, with a focus on the various formats of membrane proteins for affinity selection and the diverse affinity selection strategies used. Lastly, we discuss the challenges faced in this field and provide possible directions for future efforts.
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Affiliation(s)
- Renhua Huang
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607-7060, USA.
| | - Margaret M Kiss
- AxioMx Inc., a subsidiary of Abcam Plc, Branford, CT 06405, USA.
| | - Melissa Batonick
- AxioMx Inc., a subsidiary of Abcam Plc, Branford, CT 06405, USA.
| | - Michael P Weiner
- AxioMx Inc., a subsidiary of Abcam Plc, Branford, CT 06405, USA.
| | - Brian K Kay
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607-7060, USA.
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Jo M, Jung ST. Engineering therapeutic antibodies targeting G-protein-coupled receptors. Exp Mol Med 2016; 48:e207. [PMID: 26846450 PMCID: PMC4892866 DOI: 10.1038/emm.2015.105] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Accepted: 09/21/2015] [Indexed: 12/16/2022] Open
Abstract
G-protein–coupled receptors (GPCRs) are one of the most attractive therapeutic target classes because of their critical roles in intracellular signaling and their clinical relevance to a variety of diseases, including cancer, infection and inflammation. However, high conformational variability, the small exposed area of extracellular epitopes and difficulty in the preparation of GPCR antigens have delayed both the isolation of therapeutic anti-GPCR antibodies as well as studies on the structure, function and biochemical mechanisms of GPCRs. To overcome the challenges in generating highly specific anti-GPCR antibodies with enhanced efficacy and safety, various forms of antigens have been successfully designed and employed for screening with newly emerged systems based on laboratory animal immunization and high-throughput-directed evolution.
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Affiliation(s)
- Migyeong Jo
- Department of Bio and Nano Chemistry, Kookmin University, Seoul, Korea
| | - Sang Taek Jung
- Department of Bio and Nano Chemistry, Kookmin University, Seoul, Korea
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Selection strategies for anticancer antibody discovery: searching off the beaten path. Trends Biotechnol 2015; 33:292-301. [PMID: 25819764 DOI: 10.1016/j.tibtech.2015.02.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 02/24/2015] [Accepted: 02/25/2015] [Indexed: 01/13/2023]
Abstract
Antibody-based drugs represent one of the most successful and promising therapeutic approaches in oncology. Large combinatorial phage antibody libraries are available for the identification of therapeutic antibodies and various technologies exist for their further conversion into multivalent and multispecific formats optimized for the desired pharmacokinetics and the pathological context. However, there is no technology for antigen profiling of intact tumors to identify tumor markers targetable with antibodies. Such constraints have led to a relative paucity of tumor-associated antigens for antibody targeting in oncology. Here we review novel approaches aimed at the identification of antibody-targetable, accessible antigens in intact tumors. We hope that such advanced selection approaches will be useful in the development of next-generation antibody therapies for cancer.
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Hagemann UB, Gunnarsson L, Géraudie S, Scheffler U, Griep RA, Reiersen H, Duncan AR, Kiprijanov SM. Fully human antagonistic antibodies against CCR4 potently inhibit cell signaling and chemotaxis. PLoS One 2014; 9:e103776. [PMID: 25080123 PMCID: PMC4117600 DOI: 10.1371/journal.pone.0103776] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 06/30/2014] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND CC chemokine receptor 4 (CCR4) represents a potentially important target for cancer immunotherapy due to its expression on tumor infiltrating immune cells including regulatory T cells (Tregs) and on tumor cells in several cancer types and its role in metastasis. METHODOLOGY Using phage display, human antibody library, affinity maturation and a cell-based antibody selection strategy, the antibody variants against human CCR4 were generated. These antibodies effectively competed with ligand binding, were able to block ligand-induced signaling and cell migration, and demonstrated efficient killing of CCR4-positive tumor cells via ADCC and phagocytosis. In a mouse model of human T-cell lymphoma, significant survival benefit was demonstrated for animals treated with the newly selected anti-CCR4 antibodies. SIGNIFICANCE For the first time, successful generation of anti- G-protein coupled chemokine receptor (GPCR) antibodies using human non-immune library and phage display on GPCR-expressing cells was demonstrated. The generated anti-CCR4 antibodies possess a dual mode of action (inhibition of ligand-induced signaling and antibody-directed tumor cell killing). The data demonstrate that the anti-tumor activity in vivo is mediated, at least in part, through Fc-receptor dependent effector mechanisms, such as ADCC and phagocytosis. Anti-CC chemokine receptor 4 antibodies inhibiting receptor signaling have potential as immunomodulatory antibodies for cancer.
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Selection of potential therapeutic human single-chain Fv antibodies against cholecystokinin-B/gastrin receptor by phage display technology. BioDrugs 2013; 27:55-67. [PMID: 23344946 DOI: 10.1007/s40259-012-0007-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND AND OBJECTIVE Gastric/gastrointestinal cancers are associated with high mortality worldwide. G-protein coupled receptor (GPCR) superfamily members such as gastrin/cholecystokinin-B receptor (CCK-BR) are involved in progression of gastric tumors, thus CCK-BR is considered as a potential target for immunotherapy. However, production of functional monoclonal antibodies (mAbs) against GPCR seems to be very challenging, in part due to its integration in cell membranes and inaccessibility for selection. To tackle this problem, we implemented phage display technology and a solution-phase biopanning (SPB) scheme for production of mAbs specific to the native conformation of CCK-BR. METHODS To perform the SPB process, we utilized a synthetic biotinylated peptide corresponding to the second extracellular loop (ECL2) of CCK-BR and a semi-synthetic phage antibody library. After enzyme-linked immunosorbent assay (ELISA) screening, the CCK-BR specificity of the selected single-chain variable fragments (scFvs) were further examined using immunoblotting, whole-cell ELISA, and flow cytometry assays. RESULTS After performing four rounds of selection, we identified nine antibody clones which showed positive reactivity with the CCK-BR peptide in an ELISA assay. Of these, eight clones were unique scFv antibodies and one was a V(L) single domain antibody. Specificity analysis of the selected scFvs revealed that five of the selected scFvs recognized a denatured form of CCK-BR, while the majority of the selected scFvs were able to recognize the native conformation of CCK-BR on the surface of human gastric adenocarcinoma cells and cervical carcinoma HeLa cells. CONCLUSION For the first time, we report on the establishment of a diverse panel of scFv antibody fragments that are specific to the native conformation of CCK-BR. Based on these results, we suggest the selected scFv antibody fragments as potential agents for diagnosis, imaging, targeting, and/or immunotherapy of cancers that overexpress CCK-BR.
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Xu C, Sui J, Tao H, Zhu Q, Marasco WA. Human anti-CXCR4 antibodies undergo VH replacement, exhibit functional V-region sulfation, and define CXCR4 antigenic heterogeneity. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2007; 179:2408-18. [PMID: 17675502 DOI: 10.4049/jimmunol.179.4.2408] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The chemokine receptor CXCR4 and its ligand stromal-derived factor-1 (SDF-1/CXCL12) are essential for many biological processes and various pathological conditions. However, the relationship between CXCR4 antigenic structure and SDF-1-mediated biological responses is poorly understood. In this report, a panel of human anti-CXCR4 Abs were isolated and used to explore CXCR4 antigenic heterogeneity and function. Multiple fixed CXCR4 antigenic isoforms were detected on the surface of hemopoietic cells. Epitope mapping studies demonstrated the complex nature of the surface-exposed CXCR4 epitopes. Ab-mediated inhibition of chemotaxis correlated strongly with binding affinity, epitope recognition, as well as the level of CXCR4 isoform expression. In addition, detailed genetic analyses of these Abs showed evidence of V(H) replacement. Importantly, structural and biochemical studies demonstrated tyrosine sulfation in novel regions of the V genes that contributed bidirectionally to the binding activity of the Abs. These data provide the first evidence that functional tyrosine sulfation occurs in self-reactive Abs and suggest a potential new mechanism that may contribute to the pathogenesis of Ab-mediated autoimmune disease. These Abs also provide valuable tools to explore the selective in vivo targeting of CXCR4 isoforms that may be preferentially expressed in certain disease states and involved in steady-state CXCR4-SDF-1 homeostasis.
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Affiliation(s)
- Chen Xu
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA, USA
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Hogan S, Rookey K, Ladner R. URSA: ultra rapid selection of antibodies from an antibody phage display library. Biotechniques 2005; 38:536, 538. [PMID: 15884669 DOI: 10.2144/05384bm03] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Röthlisberger D, Pos KM, Plückthun A. An antibody library for stabilizing and crystallizing membrane proteins - selecting binders to the citrate carrier CitS. FEBS Lett 2004; 564:340-8. [PMID: 15111119 DOI: 10.1016/s0014-5793(04)00359-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Accepted: 02/23/2004] [Indexed: 11/24/2022]
Abstract
Co-crystallization of membrane proteins with antibody fragments may emerge as a general tool to facilitate crystal growth and improve crystal quality. The bound antibody fragment enlarges the hydrophilic part of the mostly hydrophobic membrane protein, thereby increasing the interaction area for possible protein-protein contacts in the crystal. Additionally, it may restrain flexible parts or lock the membrane protein in a defined conformational state. For successful co-crystallization trials, the antibody fragments must be stable in detergents during the extended period of crystal growth and must be easily produced in amounts necessary for crystallography. Therefore, we constructed a library of antibody Fab fragments from a framework subset of the HuCAL GOLD library (Morphosys, Munich, Germany). By combining the most stable and well expressed frameworks, V(H)3 and V(kappa)3, with the further stabilizing constant domains, a Fab library with the desired properties was obtained in a standard phage display format. As a proof of principle, we selected binders with phage display against the detergent-solubilized citrate transporter CitS of Klebsiella pneumoniae. We describe efficient methods for the immobilization of the membrane protein during selection, for ELISA screening, and for BIAcore evaluation. We demonstrate that the selected Fab fragments form stable complexes with native CitS and recognize conformational epitopes with affinities in the low nanomolar range.
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Affiliation(s)
- Daniela Röthlisberger
- Biochemisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
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