Structural studies of MS2 bacteriophage virus particle disassembly by nuclear magnetic resonance relaxation measurements
Structural studies of MS2 bacteriophage virus particle disassembly by nuclear magnetic resonance relaxation measurements
复制标题
DOI：
10.1016/s0006-3495(03)75117-0
复制
发表时间：
2003-06-01
影响因子：
3.4
通讯作者：
Almeida, FCL
中科院分区：
文献类型：
--
作者：
Anobom, CD;Albuquerque, SC;Almeida, FCL
本文用核磁共振弛豫测量方法研究了病毒颗粒--MS 2噬菌体的解体过程。MS 2是感染大肠杆菌的单链RNA噬菌体之一。在pH4.5时，噬菌体转变为亚稳态，如在将pH从7.0降低至4.5时观察到的核磁共振信号强度的增加所指示的。稳态荧光和圆二色光谱在pH 4.5表明，构象和二级结构的差异是不明显的，如果与噬菌体在pH 7.0相比。在pH4.5时，N-15-H-1杂原子多重量子相干（HMQC）二维谱图显示出近似40个交叉点，对应于MS 2外壳蛋白在pH4.5时移动的最多的残基。N-15谱线宽度约为30 Hz，这与转动弛豫时间为100 ns的中间体相一致。在不同温度下测量了移动的残基的平均自旋晶格弛豫时间（T-1），清楚地区分了二聚体和平衡中间体。结果表明，在MS 2噬菌体解离过程中首次存在中间体。
In this article we studied, by nuclear magnetic resonance relaxation measurements, the disassembly of a virus particle-the MS2 bacteriophage. MS2 is one of the single-stranded RNA bacteriophages that infect Escherichia coli. At pH 4.5, the phage turns to a metastable state, as is indicated by an increase in the observed nuclear magnetic resonance signal intensity upon decreasing the pH from 7.0 to 4.5. Steady-state fluorescence and circular dichroism spectra at pH 4.5 show that the difference in conformation and secondary structure is not pronounced if compared with the phage at pH 7.0. At pH 4.5, two-dimensional N-15-H-1 heteronuclear multiple quantum coherence (HMQC) spectrum shows similar to40 crosspeaks, corresponding to the most mobile residues of MS2 coat protein at pH 4.5. The N-15 linewidth is similar to30 Hz, which is consistent with an intermediate with a rotational relaxation time of 100 ns. The average spin lattice relaxation time (T-1) of the mobile residues was measured at different temperatures, clearly distinguishing between the dimer and the equilibrium intermediate. The results show, for the first time, the presence of intermediates in the process of dissociation of the MS2 bacteriophage.