PULSE DIPOLAR ESR STUDY ON INTERACTION OF HIV-1 NUCLEOCAPSID PROTEIN NCP7

HIV-1 核衣壳蛋白 NCP7 相互作用的脉冲偶极 ESR 研究

• 批准号: 8364052
• 负责人: PETER P BORBAT
• 金额: $ 0.14万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8364052
• 关键词: Antiviral Therapy; Base Pairing; Binding Sites; DNA; DNA Sequence; DNA biosynthesis; Dimerization; Enzymes; Exhibits; Fingers; Funding; Genetic Recombination; Genomics; Grant; HIV-1; Homodimerization; Life Cycle Stages; Mediating; Molecular Chaperones; National Center for Research Resources; Nucleic Acids; Nucleocapsid Proteins; Oligonucleotides; Physiologic pulse; Play; Principal Investigator; Process; RNA; RNA-Directed DNA Polymerase; Reaction; Research; Research Infrastructure; Resources; Response Elements; Reverse Transcription; Source; Structure; Surface; Technology; Transactivation; United States National Institutes of Health; Universities; Viral; Viral Proteins; Zinc Fingers; cost; ds-DNA; flexibility; melting; stem; strong-stop (+) DNA

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Prof. Charles P. Scholes from Albany University is actively studying the mechanisms underlying HIV-1 replication. A critical step in HIV-1 replication is reverse transcription of HIV-1 genomic RNA to double-stranded DNA by reverse transcriptase (RT). Two viral proteins, the RT enzyme and a small nucleocapsid protein NCp7, which is well-known nucleic acid chaperone direct this process. At the beginning of the linear DNA synthesis, the newly made minus-strand strong-stop DNA ((-)ssDNA) is transferred to the 3'end of the genomic RNA by means of an hybridization reaction between transactivation response element (TAR) RNA and cTAR DNA sequences. Since both TAR sequences exhibit stable hairpin structures, NCp7 needs to destabilize the TAR structures in order to chaperone their hybridization. NCp7 is characterized by two zinc fingers that plays a key role in HIV-1 life cycle and presents a promising target for an antiviral therapy. It has been shown that NCp7 chaperones the first strand transfer by promoting the annealing of the complementary transactivation response element (TAR) RNA and cTAR DNA stem-loop sequences. This critically relies on NCp7 ability to transiently melt their terminal base pairs. The destabilization activity of NCp7 is mediated by a hydrophobic plateau at the surface of the folded zinc fingers, which restricted the oligonucleotide flexibility. The destabilizing of the TAR and cTAR sequences can be mediated by a single finger motif, while the annealing activity requires the two fingers. NCp7 induces a limited destabilization of the primer binding site (PBS) stem-loops involved in the second strand transfer. However, NCp7 can chaperone their homodimerization, by stabilizing the annealing of their partly self-complementary loops. The propensity of NCp7 to promote the dimerization of partly complementary sequences may favor secondary contacts between viral sequences and thus, recombination and viral diversity. Moreover, NCp7 promotes the second strand transfer, by chaperoning a kissing-loop intermediate, through an extension of the loops and a weakening of the upper base pair of the stem.

该子项目是利用资源的众多研究子项目之一 由 NIH/NCRR 资助的中心拨款提供。子项目的主要支持 并且子项目的首席研究员可能是由其他来源提供的， 包括其他 NIH 来源。 子项目可能列出的总成本 代表子项目使用的中心基础设施的估计数量， NCRR 赠款不直接向子项目或子项目工作人员提供资金。 奥尔巴尼大学的 Charles P. Scholes 教授正在积极研究 HIV-1 复制的机制。 HIV-1 复制的关键步骤是通过逆转录酶 (RT) 将 HIV-1 基因组 RNA 逆转录为双链 DNA。两种病毒蛋白，即 RT 酶和一种小核衣壳蛋白 NCp7（众所周知的核酸伴侣）指导这一过程。在线性 DNA 合成开始时，新制备的负链强终止 DNA ((-)ssDNA) 通过反式激活反应元件 (TAR) RNA 之间的杂交反应转移到基因组 RNA 的 3' 端和cTAR DNA 序列。由于两个 TAR 序列均表现出稳定的发夹结构，因此 NCp7 需要破坏 TAR 结构的稳定性以陪伴其杂交。 NCp7 的特点是有两个锌指，在 HIV-1 生命周期中发挥着关键作用，并为抗病毒治疗提供了一个有希望的靶标。 研究表明，NCp7 通过促进互补反式激活反应元件 (TAR) RNA 和 cTAR DNA 茎环序列的退火来陪伴第一链转移。这主要依赖于 NCp7 瞬时熔化其末端碱基对的能力。 NCp7 的去稳定活性是由折叠锌指表面的疏水平台介导的，这限制了寡核苷酸的灵活性。 TAR 和 cTAR 序列的不稳定可以由单个指状基序介导，而退火活性需要两个指状基序。 NCp7 会引起参与第二链转移的引物结合位点 (PBS) 茎环的有限不稳定。然而，NCp7 可以通过稳定其部分自互补环的退火来陪伴其同二聚化。 NCp7 促进部分互补序列二聚化的倾向可能有利于病毒序列之间的二次接触，从而有利于重组和病毒多样性。此外，NCp7 通过环的延伸和茎上部碱基对的弱化，陪伴亲环中间体，促进第二链转移。