Recognition of Viral DNA by APOBEC3 Proteins and their Antagonization by HIV Vif

APOBEC3 蛋白对病毒 DNA 的识别及其 HIV Vif 的拮抗作用

• 批准号: 8992425
• 负责人: Yong Xiong
• 金额: $ 41.49万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-15 至 2020-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8992425
• 关键词: Acquired Immunodeficiency Syndrome; Affinity; Antiviral Agents; Binding; Biochemical; Biochemistry; Biological Assay; Biophysics; C-terminal; Catalytic Domain; Cells; Chimeric Proteins; Communities; Comorbidity; Complement; Complex; Cytidine Deaminase; DNA; DNA Sequence; DNA-Protein Interaction; Deaminase; Electron Microscopy; Fluorescence; Genome; Goals; HIV; HIV Infections; HIV-1; Host Defense; Host Defense Mechanism; Human; Immune; Immune system; Infection; Knowledge; Length; Malignant Neoplasms; Maps; Mediating; Methods; Molecular; Mutagenesis; Mutate; Pathway interactions; Positioning Attribute; Protein Engineering; Protein Family; Proteins; Recruitment Activity; Research; Research Project Grants; Reverse Transcription; Solubility; Spectrum Analysis; Structure; System; Therapeutic; Viral; Viral Genome; Viral Proteins; Virion; Virus Inhibitors; Work; X-Ray Crystallography; antiretroviral therapy; base; combat; design; enzyme mechanism; inhibitor/antagonist; innovation; multicatalytic endopeptidase complex; novel; pathogen; preference; prevent; public health relevance; structural biology; success; three dimensional structure; tool; ubiquitin-protein ligase; viral DNA

 DESCRIPTION (provided by applicant): The host immune system has diverse defenses that combat viral invasions, such as infection by human immunodeficiency virus type 1 (HIV-1), which causes acquired immunodeficiency syndrome (AIDS) and major comorbidities such as cancer. The human antiviral proteins APOBEC3G (A3G) and APOBEC3F (A3F) are cellular cytidine deaminases that suppress HIV infection by hypermutation of viral genome and physically blocking reverse transcription, which prevents the accumulation of HIV-1 DNA. To evade this host defense mechanism, HIV expresses the virion infectivity factor (Vif), which hijacks a cellular E3 ubiquitin ligase complex to target A3F/G for proteasome-mediated degradation. Despite intense research and progress in the structure elucidation of a Vif-containing E3 ubiquitin ligase complex, the mechanisms by which APOBEC3 (A3) proteins select specific viral DNA sequences and the molecular interactions employed by Vif to recognize A3 proteins remain unclear. Our overall goal is to establish the biochemical and structural principles by which A3 proteins mutate viral DNA and HIV-1 Vif sequesters the A3 proteins. To achieve this goal, we will use a combination of biochemistry, biophysics, structural biology, and cell-based functional assays to dissect the interactions between different A3 proteins and substrate DNAs, interrogate the assembly of the Vif/E3 ligase/A3 complex, and obtain detailed three-dimensional structural information of these interaction complexes. We have devised innovative strategies to capture structures of multiple A3 proteins in complex with their preferred DNA substrates. These results will provide essential information to help decipher the DNA recognition and sequence preference mechanisms of these enzymes. We will further delineate the structural details of Vif-A3 protein interactions by constructing rationally designed structural targets that represent the molecular interfaces. We will also investigate the substrate assembly pathway using spectroscopy methods and determine the structure of the completely assembled molecular complex containing A3, Vif and the E3 ubiquitin ligase. The success of the proposed work will significantly advance our understanding of an important host immune defense system against HIV and viral evasion strategy. Information obtained will facilitate the design of Vif inhibitors as a novel class of antiretroviral therapy to complement the existing armamentarium.