Maturation of a tetravirus capsid alters the dynamic properties and creates a metastable complex
Maturation of a tetravirus capsid alters the dynamic properties and creates a metastable complex
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DOI：
10.1016/j.virol.2005.01.017
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发表时间：
2005-03-30
期刊：
影响因子：
3.7
通讯作者：
Johnson, JE
中科院分区：
文献类型：
--
作者：
Bothner, B;Taylor, D;Johnson, JE
将单体蛋白质亚基组装成病毒衣壳是一个精细调节的分子过程。为了应对环境条件的微妙变化，这种超分子复合物可以显着重组。确定控制这种结构的力量和亚基的合作行动对生物学和纳米技术有影响。小二十面体RNA四病毒家族成员Nudaurelia omega capensis（N ω V）和棉铃虫矮化病毒（HaSV）可以作为前病毒体纯化，并且可以通过pH的下降诱导成熟为衣壳。在这项研究中，使用FT-IR对衣壳二级结构的比较显示，原衣壳具有比衣壳更多的α-螺旋含量，支持了螺旋到卷曲的转变对于成熟可能是重要的这一提议。这两种状态的动力学性质进行了探讨，使用有限的蛋白水解和肽质量映射，以确定显着的灵活性区域。有趣的是，蛋白酶切割的初始位点是高分辨率模型中内部的N和C末端结构域，以及亚基间表面。使用FT-IR对两种颗粒形式的进一步比较显示，响应于热应力，前病毒在窄的温度范围（类似于5摄氏度）内以合作的方式分解和展开。特别地，在宽范围的pH和离子条件下稳定并且对蛋白水解更具抗性的衣壳形式在比原衣壳形式更低的温度下响应热应力。这表明亚稳态是组装的最终产物。(c)2005年爱思唯尔公司All rights reserved.
The assembly of monomeric protein subunits into a viral capsid is a finely tuned molecular process. In response to subtle changes in environmental conditions, this supramolecular complex can dramatically reorganize. Defining the forces that control this structure and the cooperative action of subunits has implications for biology and nanotechnology. The small icosahedral RNA tetravirus family members Nudaurelia omega capensis (N omega V) and Helicoverpa armigera stunt virus (HaSV) can be purified as provirions, and maturation to capsids can be induced by a drop in pH. In this study, a comparison of capsid secondary structure using FT-IR revealed that the procapsid has more alpha-helical content than the capsid, supporting the proposal that helix to coil transition may be important for maturation. The dynamic properties of the two states were probed using limited proteolysis and peptide mass mapping to identify regions of significant flexibility. Interestingly, the initial sites of protease cleavage were the N and C terminal domains that are internal in high-resolution models, and to inter-subunit surfaces. Further comparison of the two particle forms using FT-IR revealed that in response to thermal stress, the provirion disassembles and unfolds in a cooperative manner over a narrow temperature range (similar to 5 degrees C). Paradoxically, the capsid form, which is stable in a wide range of pH and ionic conditions and is more resistant to proteolysis, responds to thermal stress at a lower temperature than the procapsid form. This suggests that a metastable state is the end product of assembly. (c) 2005 Elsevier Inc. All rights reserved.