呼肠孤病毒中间亚病毒颗粒的圆二色性。阐明单价阳离子对脱壳作用的特异性机制。

Circular dichroism of intermediate subviral particles of reovirus. Elucidation of the mechanism underlying the specific monovalent cation effects on uncoating.

Borsa J, Sargent M D, Kay C M, Oikawa K

Biochim Biophys Acta. 1976 Dec 21;451(2):619-27. doi: 10.1016/0304-4165(76)90157-4.

Abstract

Circular dichroic (CD) spectra of purified intermediate subviral particles of reovirus were determined in the presence of different monovalent cations. 2. The CD spectra reveal that reo intermediate subviral particles can exist in two conformationally different forms. The two forms are readily distinguished by comparison of their ellipticities in the wavelength regions 210 nm and 220 nm, with a Na+-induced form exhibiting a reduced negative ellipticity relative to a Cs+-induced form. 3. The transition between the Na+- and Cs+-induced forms is reversible by manipulation of the species of monovalent cation present and appears to be temperature independent. 4. Temperature variation studies on dilute suspensions of particles indicate that the Na+-induced form is stable, whereas the Cs+-induced from undergoes a second transition, temperature dependent and irreversible, to become a viral core. 5. A model is presented relating these observations to the known properties of reovirus uncoating and transcriptase activation.

摘要

在不同单价阳离子存在的情况下，测定了呼肠孤病毒纯化的中间亚病毒颗粒的圆二色性（CD）光谱。2. CD光谱显示，呼肠孤病毒中间亚病毒颗粒可以两种构象不同的形式存在。通过比较它们在210纳米和220纳米波长区域的椭圆率，这两种形式很容易区分，与Cs⁺诱导的形式相比，Na⁺诱导的形式表现出降低的负椭圆率。3. 通过操纵存在的单价阳离子种类，Na⁺和Cs⁺诱导形式之间的转变是可逆的，并且似乎与温度无关。4. 对颗粒稀释悬浮液的温度变化研究表明，Na⁺诱导的形式是稳定的，而Cs⁺诱导的形式会发生第二次转变，这种转变依赖于温度且不可逆，从而变成病毒核心。5. 提出了一个模型，将这些观察结果与呼肠孤病毒脱壳和转录酶激活的已知特性联系起来。