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Zhang Z, He M, Bai S, Zhang F, Jiang J, Zheng Q, Gao S, Yan X, Li S, Gu Y, Xia N. T = 4 Icosahedral HIV-1 Capsid As an Immunogenic Vector for HIV-1 V3 Loop Epitope Display. Viruses 2018; 10:v10120667. [PMID: 30486318 PMCID: PMC6316451 DOI: 10.3390/v10120667] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/21/2018] [Accepted: 11/23/2018] [Indexed: 11/19/2022] Open
Abstract
The HIV-1 mature capsid (CA) assumes an amorphous, fullerene conical configuration due to its high flexibility. How native CA self-assembles is still unclear despite having well-defined structures of its pentamer and hexamer building blocks. Here we explored the self-assembly of an engineered capsid protein built through artificial disulfide bonding (CA N21C/A22C) and determined the structure of one fraction of the globular particles. CA N21C/A22C was found to self-assemble into particles in relatively high ionic solutions. These particles contained disulfide-bonding hexamers as determined via non-reducing SDS-PAGE, and exhibited two major components of 57.3 S and 80.5 S in the sedimentation velocity assay. Particles had a globular morphology, approximately 40 nm in diameter, in negative-staining TEM. Through cryo-EM 3-D reconstruction, we determined a novel T = 4 icosahedral structure of CA, comprising 12 pentamers and 30 hexamers at 25 Å resolution. We engineered the HIV-1 V3 loop to the CA particles, and found the resultant particles resembled the morphology of their parental particles in TEM, had a positive reaction with V3-specific neutralizing antibodies, and conferred neutralization immunogenicity in mice. Our results shed light on HIV CA assembly and provide a particulate CA for epitope display.
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Affiliation(s)
- Zhiqing Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China.
| | - Maozhou He
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China.
| | - Shimeng Bai
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Life Sciences, Xiamen University, Xiamen 361102, China.
| | - Feng Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China.
| | - Jie Jiang
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Life Sciences, Xiamen University, Xiamen 361102, China.
| | - Qingbing Zheng
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China.
| | - Shuangquan Gao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China.
| | - Xiaodong Yan
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China.
- Department of Chemistry and Biochemistry and Division of Biological Sciences, University of California-San Diego, San Diego, CA 92093-0378, USA.
| | - Shaowei Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China.
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Life Sciences, Xiamen University, Xiamen 361102, China.
| | - Ying Gu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China.
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Life Sciences, Xiamen University, Xiamen 361102, China.
| | - Ningshao Xia
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China.
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Life Sciences, Xiamen University, Xiamen 361102, China.
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Expression, Purification and Characterization of Hiv-1 Capsid Precursor Protein p41. Protein J 2018; 37:194-202. [PMID: 29508209 DOI: 10.1007/s10930-018-9763-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) has been a global epidemic since 1983; yet, the virology and immunology related to HIV-1 remain elusive. Furthermore, as there is still no effective chemoprophylaxis or vaccine to treat patients with HIV-1, most research focuses on strategies to prevent HIV-1 infection, such as with antiviral drugs, novel therapeutics, or improved diagnostic kits. The HIV-1 Gag precursor protein (p55)-comprising the matrix (MA/p17), capsid (CA/p24), and nucleocapsid (NC/p7) protein domains-is the main structural HIV-1 protein, and is uniquely responsible for virion assembly within the virus life cycle. Recently, the immature and mature capsid structures were solved; however, the precursor protein structure is still unknown. Here, we expressed two subtypes of HIV-1 MA-CA stretch of the Gag protein, referred to as p41, in a bacterial expression system. We characterized the purified p41 protein, and showed its superior antigenicity over that of p24, highlighting the potential influence of the p17 domain on p24 structure. We further showed that p41 has good immunogenicity to induce an antibody response in mice. These results will aid future investigations into the HIV-1 capsid precursor structure, and potentially contribute to improving the design of diagnostic kits.
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Xin L, Yu H, Hong Q, Bi X, Zhang X, Zhang Z, Kong Z, Zheng Q, Gu Y, Zhao Q, Zhang J, Li S, Xia N. Identification of Strategic Residues at the Interface of Antigen-Antibody Interactions by In Silico Mutagenesis. Interdiscip Sci 2017; 10:438-448. [PMID: 28560699 DOI: 10.1007/s12539-017-0242-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 04/17/2017] [Accepted: 05/22/2017] [Indexed: 11/24/2022]
Abstract
Structural information pertaining to antigen-antibody interactions is fundamental in immunology, and benefits structure-based vaccine design. Modeling of antigen-antibody immune complexes from co-crystal structures or molecular docking simulations provides an extensive profile of the epitope at the interface; however, the key amino acids involved in the interaction must be further clarified, often through the use of experimental mutagenesis and subsequent binding assays. Here, we describe an in silico mutagenesis method to identify key sites at antigen-antibody interfaces, using significant increase in pH-dependency energy among saturated point mutations. Through a comprehensive analysis of the crystal structures of three antigen-antibody immune complexes, we show that a cutoff value of 1 kcal/mol of increased interaction energy provides good congruency with the experimental non-binding mutations conducted in vitro. This in silico mutagenesis strategy, in association with energy calculations, may provide an efficient tool for antibody-antigen interface analyses, epitope optimization, and/or conformation prediction in structure-based vaccine design.
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Affiliation(s)
- Lu Xin
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China
| | - Hai Yu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China. .,School of Public Health, Xiamen University, Xiamen, 361005, Fujian, People's Republic of China.
| | - Qiyang Hong
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China
| | - Xingjian Bi
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China
| | - Xiao Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China
| | - Zhiqing Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China
| | - Zhibo Kong
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China
| | - Qingbing Zheng
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China
| | - Ying Gu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China
| | - Qinjian Zhao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China
| | - Jun Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China
| | - Shaowei Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China
| | - Ningshao Xia
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, Xiamen University, Xiamen, 361002, Fujian, People's Republic of China
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