Rowe A, Burlison J, Macadam A J, Minor P D
Division of Virology, National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Herts, EN6 3QG, United Kingdom.
Virology. 2001 Oct 10;289(1):45-53. doi: 10.1006/viro.2001.1111.
Previously we have shown that polioviruses with mutations that disrupt the predicted secondary structure of the 5' noncoding region of domain V are temperature sensitive for growth. Non-temperature-sensitive revertant viruses had mutations that re-formed secondary structure by a direct back mutation of changes in the opposite strand. We mutated unpaired regions and selected revertants of viruses with single base deletions, where no obvious back mutation was available in order to gain information on secondary structure. Results indicated that conservation of length of a three base loop between two double-stranded stems was essential for a functional domain V to form. The requirement for the unpaired "hinge" base at 484 which is implicated in the attenuation of Sabin 2 was also confirmed. Results also underline the necessity for functional folding over local secondary structure stability.
此前我们已经表明，脊髓灰质炎病毒若发生突变，破坏了结构域V 5'非编码区预测的二级结构，则其生长对温度敏感。非温度敏感的回复病毒发生的突变通过相反链上变化的直接回复突变重新形成了二级结构。我们对未配对区域进行了突变，并选择了具有单碱基缺失的病毒的回复株，在这些病毒中没有明显的回复突变，以便获取有关二级结构的信息。结果表明，两个双链茎之间一个三碱基环的长度保守性对于功能性结构域V的形成至关重要。对484位未配对的“铰链”碱基的需求也得到了证实，该碱基与Sabin 2株的减毒有关。结果还强调了功能折叠相对于局部二级结构稳定性的必要性。
