Center for Nano and Molecular Science and Technology and Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, USA.
J Am Chem Soc. 2009 Oct 28;131(42):15534-43. doi: 10.1021/ja9070046.
The human immunodeficiency virus type-1 (HIV-1) nucleocapsid (NC) protein is believed to be unique among the nucleic acid (NA) binding proteins encoded by this retrovirus in being highly multifunctional and relatively nonsequence-specific. Underlying many of NC's putative functions, including for example its chaperon-like activity for various steps of HIV-1 reverse transcription, is NC's ability to partially melt short double-stranded regions of structured NAs, which is essentially a consequence of NC's general binding preference for single-stranded bases. Herein we report a different, previously undiscovered, mode of NC/NA interaction, i.e., NC-induced sharp bending of short segments of fully duplexed DNA/DNA and DNA/RNA. We use single-molecule fluorescence resonance energy transfer (SM-FRET) in vitro to probe NC-induced NA bending and associated heterogeneous conformational dynamics for model NC/NA complexes. NC-induced NA bending may have important biological roles in the previously reported NC-mediated condensation of duplex proviral DNA in the HIV-1 life cycle.
人类免疫缺陷病毒 1 型（HIV-1）核衣壳（NC）蛋白被认为是该逆转录病毒编码的核酸（NA）结合蛋白中非常独特的一种，具有高度多功能性和相对非序列特异性。在 NC 的许多假定功能中，包括例如其对 HIV-1 逆转录的各个步骤的伴侣样活性，是 NC 部分融化结构 NA 的短双链区域的能力，这实质上是 NC 对单链碱基的普遍结合偏好的结果。在此，我们报告了一种以前未发现的 NC/NA 相互作用的不同模式，即 NC 诱导的完全双链 DNA/DNA 和 DNA/RNA 的短片段的急剧弯曲。我们使用体外单分子荧光共振能量转移（SM-FRET）来探测 NC 诱导的 NA 弯曲以及模型 NC/NA 复合物的相关异质构象动力学。NC 诱导的 NA 弯曲可能在 HIV-1 生命周期中先前报道的 NC 介导的双链前病毒 DNA 凝聚中具有重要的生物学作用。
