丝状噬菌体 Pf1 的单链 DNA 基因组的结构模型。
A structural model for the single-stranded DNA genome of filamentous bacteriophage Pf1.
机构信息
College of Science and Engineering and Faculty of Pharmacy, Iwaki-Meisei University, Chuodai-Iino 5-5-1, Iwaki, Fukushima 970-8551, Japan.
出版信息
Biochemistry. 2010 Mar 2;49(8):1737-43. doi: 10.1021/bi901323a.
The filamentous bacteriophage Pf1, which infects strain PAK of Pseudomonas aeruginosa, is a flexible filament ( approximately 2000 x 6.5 nm) consisting of a covalently closed DNA loop of 7349 nucleotides sheathed by 7350 copies of a 46-residue alpha-helical subunit. The subunit alpha-helices, which are inclined at a small average angle ( approximately 16 degrees ) from the virion axis, are arranged compactly around the DNA core. Orientations of the Pf1 DNA nucleotides with respect to the filament axis are not known. In this work we report and interpret the polarized Raman spectra of oriented Pf1 filaments. We demonstrate that the polarizations of DNA Raman band intensities establish that the nucleotide bases of packaged Pf1 DNA are well ordered within the virion and that the base planes are positioned close to parallel to the filament axis. The present results are combined with a previously proposed projection of the intraviral path of Pf1 DNA [Liu, D. J., and Day, L. A. (1994) Science 265, 671-674] to develop a novel molecular model for the Pf1 assembly.
丝状噬菌体 Pf1 感染铜绿假单胞菌 PAK 菌株，是一种由 7349 个核苷酸组成的环状 DNA 环包裹着 7350 个 46 个氨基酸组成的α-螺旋亚基组成的灵活丝状噬菌体（约 2000×6.5nm）。亚基α-螺旋以小平均角度（约 16 度）从病毒轴倾斜，紧密排列在 DNA 核心周围。Pf1 DNA 核苷酸相对于纤维轴的取向尚不清楚。在这项工作中，我们报告并解释了定向 Pf1 纤维的偏振拉曼光谱。我们证明，包装的 Pf1 DNA 核苷酸的碱基在病毒内排列整齐，碱基平面接近平行于纤维轴，这是通过 DNA 拉曼带强度的偏振确定的。目前的结果与先前提出的 Pf1 DNA 病毒内路径的预测相结合，为 Pf1 组装提出了一种新的分子模型。
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