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Buchholz I, McDonnell T, Nestler P, Tharad S, Kulke M, Radziszewska A, Ripoll VM, Schmidt F, Hammer E, Toca-Herrera JL, Rahman A, Delcea M. Specific domain V reduction of beta-2-glycoprotein I induces protein flexibility and alters pathogenic antibody binding. Sci Rep 2021; 11:4542. [PMID: 33633190 PMCID: PMC7907366 DOI: 10.1038/s41598-021-84021-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 02/10/2021] [Indexed: 01/31/2023] Open
Abstract
Beta-2-glycoprotein I (β2GPI) is a blood protein and the major antigen in the autoimmune disorder antiphospholipid syndrome (APS). β2GPI exists mainly in closed or open conformations and comprises of 11 disulfides distributed across five domains. The terminal Cys288/Cys326 disulfide bond at domain V has been associated with different cysteine redox states. The role of this disulfide bond in conformational dynamics of this protein has not been investigated so far. Here, we report on the enzymatic driven reduction by thioredoxin-1 (recycled by Tris(2-carboxyethyl)phosphine; TCEP) of β2GPI. Specific reduction was demonstrated by Western blot and mass spectrometry analyses confirming majority targeting to the fifth domain of β2GPI. Atomic force microscopy images suggested that reduced β2GPI shows a slightly higher proportion of open conformation and is more flexible compared to the untreated protein as confirmed by modelling studies. We have determined a strong increase in the binding of pathogenic APS autoantibodies to reduced β2GPI as demonstrated by ELISA. Our study is relevant for understanding the effect of β2GPI reduction on the protein structure and its implications for antibody binding in APS patients.
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Affiliation(s)
- Ina Buchholz
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany
- ZIK HIKE, University of Greifswald, Greifswald, Germany
| | - Thomas McDonnell
- Division of Biochemical Engineering, Bernard Katz Institute, University College London, London, UK
| | - Peter Nestler
- Institute of Physics, University of Greifswald, Greifswald, Germany
| | - Sudarat Tharad
- Institute for Biophysics, University of Natural Resources and Life Sciences Vienna, Vienna, Austria
| | - Martin Kulke
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Anna Radziszewska
- Centre for Adolescent Rheumatology Versus Arthritis at UCL, UCLH, GOSH, London, UK
- Division of Medicine, Centre for Rheumatology, University College London, London, UK
| | - Vera M Ripoll
- Division of Medicine, Centre for Rheumatology, University College London, London, UK
| | - Frank Schmidt
- Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
- Proteomics Core, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Elke Hammer
- Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Greifswald, Greifswald, Germany
| | - Jose L Toca-Herrera
- Institute for Biophysics, University of Natural Resources and Life Sciences Vienna, Vienna, Austria
| | - Anisur Rahman
- Division of Medicine, Centre for Rheumatology, University College London, London, UK.
| | - Mihaela Delcea
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany.
- ZIK HIKE, University of Greifswald, Greifswald, Germany.
- DZHK (German Centre for Cardiovascular Research), Partner Site Greifswald, Greifswald, Germany.
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Leu SJJ, Lee TY, Cheng SW, Tsai MY, Lin YS, Chiou TJ, Huang KY, Chiang AN. Structural and functional characterization of β 2 -glycoprotein I domain 1 in anti-melanoma cell migration. Cancer Sci 2019; 110:1974-1986. [PMID: 31012976 PMCID: PMC6549912 DOI: 10.1111/cas.14030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 04/17/2019] [Accepted: 04/17/2019] [Indexed: 12/20/2022] Open
Abstract
We previously found that circulating β2‐glycoprotein I inhibits human endothelial cell migration, proliferation, and angiogenesis by diverse mechanisms. In the present study, we investigated the antitumor activities of β2‐glycoprotein I using structure‐function analysis and mapped the critical region within the β2‐glycoprotein I peptide sequence that mediates anticancer effects. We constructed recombinant cDNA and purified different β2‐glycoprotein I polypeptide domains using a baculovirus expression system. We found that purified β2‐glycoprotein I, as well as recombinant β2‐glycoprotein I full‐length (D12345), polypeptide domains I‐IV (D1234), and polypeptide domain I (D1) significantly inhibited melanoma cell migration, proliferation and invasion. Western blot analyses were used to determine the dysregulated expression of proteins essential for intracellular signaling pathways in B16‐F10 treated with β2‐glycoprotein I and variant recombinant polypeptides. Using a melanoma mouse model, we found that D1 polypeptide showed stronger potency in suppressing tumor growth. Structural analysis showed that fragments A and B within domain I would be the critical regions responsible for antitumor activity. Annexin A2 was identified as the counterpart molecule for β2‐glycoprotein I by immunofluorescence and coimmunoprecipitation assays. Interaction between specific amino acids of β2‐glycoprotein I D1 and annexin A2 was later evaluated by the molecular docking approach. Moreover, five amino acid residues were selected from fragments A and B for functional evaluation using site‐directed mutagenesis, and P11A, M42A, and I55P mutations were shown to disrupt the anti‐melanoma cell migration ability of β2‐glycoprotein I. This is the first study to show the therapeutic potential of β2‐glycoprotein I D1 in the treatment of melanoma progression.
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Affiliation(s)
- Shr-Jeng Jim Leu
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan.,Department of Education and Research, Taipei City Hospital, Taipei, Taiwan
| | - Tzong-Yi Lee
- Warshel Institute for Computational Biology, Chinese University of Hong Kong, Shenzhen, China
| | - Shu-Wei Cheng
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
| | - Meng-Ying Tsai
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
| | - Yu-Shan Lin
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
| | - Tzeon-Jye Chiou
- Division of Transfusion Medicine, Taipei Veterans General Hospital, and School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Kai-Yao Huang
- Warshel Institute for Computational Biology, Chinese University of Hong Kong, Shenzhen, China
| | - An-Na Chiang
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
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