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Wang Z, Xie X, He Z, Sun Z, Zhang Y, Mao F, Pei H, Zhang S, Hammock BD, Liu X. Development of Shark Single Domain Antibodies Specific for Human α-Fetoprotein and the Multimerization Strategy in Serum Detection. Anal Chem 2024; 96:4242-4250. [PMID: 38408370 DOI: 10.1021/acs.analchem.3c05675] [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: 02/28/2024]
Abstract
Sensitive detection of cancer biomarkers can contribute to the timely diagnosis and treatment of diseases. In this study, the whitespotted bamboo sharks were immunized with human α-fetoprotein (AFP), and a phage-displayed variable new antigen receptor (VNAR) single domain antibody library was constructed. Then four unique VNARs (VNAR1, VNAR11, VNAR21, and VNAR25) against AFP were isolated from the library by biopanning for the first time. All of the sequences belong to type II of VNAR, and the VNAR11 was much different from the rest of the three sequences. Then VNAR1 and VNAR11 were selected to fuse with the C4-binding protein α chain (C4bpα) sequence and efficiently expressed in the Escherichia coli system. Furthermore, a VNAR-C4bpα-mediated sandwich chemiluminescence immunoassay (VSCLIA) was developed for the detection of AFP in human serum samples. After optimization, the VSCLIA showed a limit of detection of 0.74 ng/mL with good selectivity and accuracy. Moreover, the results of clinical serum samples detected by the VSCLIA were confirmed by an automatic immunoanalyzer in the hospital, indicating its practical application in actual samples. In conclusion, the novel antibody element VNAR exhibits great potential for immunodiagnosis, and this study also provides a new direction and experimental basis for AFP detection.
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Affiliation(s)
- Zheming Wang
- School of Food Science and Engineering, Hainan University, Haikou 570228, China
| | - Xiaoxia Xie
- School of Food Science and Engineering, Hainan University, Haikou 570228, China
| | - Zhenyun He
- School of Food Science and Engineering, Hainan University, Haikou 570228, China
| | - Zhichang Sun
- School of Food Science and Engineering, Hainan University, Haikou 570228, China
| | - Yongli Zhang
- School of Food Science and Engineering, Hainan University, Haikou 570228, China
| | - Fujing Mao
- School of Food Science and Engineering, Hainan University, Haikou 570228, China
| | - Hua Pei
- Department of Clinical Laboratory, The Second Affiliated Hospital of Hainan Medical University, Haikou 570311, China
| | - Sihang Zhang
- School of Food Science and Engineering, Hainan University, Haikou 570228, China
| | - Bruce D Hammock
- Department of Entomology and Nematology, and UC Davis Comprehensive Cancer Center, University of California, Davis, California 95616, United States
| | - Xing Liu
- School of Food Science and Engineering, Hainan University, Haikou 570228, China
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Han Q, Su Y, Smith KM, Binns J, Drummond CJ, Darmanin C, Greaves TL. Probing ion-binding at a protein interface: Modulation of protein properties by ionic liquids. J Colloid Interface Sci 2023; 650:1393-1405. [PMID: 37480654 DOI: 10.1016/j.jcis.2023.07.045] [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: 04/25/2023] [Revised: 07/05/2023] [Accepted: 07/08/2023] [Indexed: 07/24/2023]
Abstract
Ions are important to modulate protein properties, including solubility and stability, through specific ion effects. Ionic liquids (ILs) are designer salts with versatile ion combinations with great potential to control protein properties. Although protein-ion binding of common metals is well-known, the IL effect on proteins is not well understood. Here, we employ the model protein lysozyme in dilute and concentrated IL solutions to determine the specific ion binding effect on protein phase behaviour, activity, size and conformational change, aggregation and intermolecular interactions. A combination of spectroscopic techniques, activity assays, small-angle X-ray scattering, and crystallography highlights that ILs, particularly their anions, bind to specific sites in the protein hydration layer via polar contacts on charged, polar and aromatic residues. The specific ion binding can induce more flexible loop regions in lysozyme, while the ion binding in the bulk phase can be more dynamic in solution. Overall, the protein behaviour in ILs depends on the net effect of nonspecific interactions and specific ion binding. Compared to formate, the nitrate anion induced high protein solubility, low activity, elongated shape and aggregation, which is largely owing to its higher propensity for ion binding. These findings provide new insights into protein-IL binding interactions and using ILs to modulate protein properties.
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Affiliation(s)
- Qi Han
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Yuyu Su
- School of Engineering, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Kate M Smith
- Australian Synchrotron, Australian Nuclear Science and Technology Organisation, 800 Blackburn Road, Clayton, VIC 3168, Australia; Swiss Light Source, Paul Scherrer Institute, Forschungsstrasse 111, Villigen-PSI, 5232 Villigen, Switzerland
| | - Jack Binns
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Calum J Drummond
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia.
| | - Connie Darmanin
- La Trobe Institute for Molecular Science, Department of Mathematical and Physical Sciences, School of Computing Engineering and Mathematical Science, La Trobe University, Bundoora, VIC 3086, Australia.
| | - Tamar L Greaves
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia.
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