Bishop N E, Anderson D A
Hepatitis Research Unit, Macfarlane Burnet Centre for Medical Research, Fairfield, Victoria, Australia.
Virology. 1993 Dec;197(2):616-23. doi: 10.1006/viro.1993.1636.
Stable provirions of hepatitis A virus containing up to 62% VP0 were purified from infected BS-C-1 cells by sucrose density gradient ultracentrifugation, and conversion of these provirions to virions through maturation cleavage of VP0 capsid protein was demonstrated. VP0 cleavage was slow but linear over 7 days at 37 degrees, with mature virions containing between 3 and 7 copies of VP0 in separate experiments. Cleavage of approximately 25% of VP0 molecules (15 copies) was accompanied by a twofold increase in specific infectivity. Particles with reduced levels of VP0 were observed to sediment more rapidly in sucrose than VP0-rich provirions, reflecting conformational changes in the particles. The kinetics and temperature-dependence of VP0 cleavage further suggest that such conformational changes accompanying VP0 cleavage are necessary for the formation of subsequent catalytic sites.
通过蔗糖密度梯度超速离心从感染的BS-C-1细胞中纯化出含有高达62% VP0的甲型肝炎病毒稳定前病毒颗粒，并证明了这些前病毒颗粒通过VP0衣壳蛋白的成熟切割转化为病毒颗粒。在37℃下，VP0切割在7天内缓慢但呈线性，在单独的实验中，成熟病毒颗粒含有3至7个VP0拷贝。大约25%的VP0分子（15个拷贝）的切割伴随着比感染性的两倍增加。观察到VP0水平降低的颗粒在蔗糖中的沉降速度比富含VP0的前病毒颗粒更快，这反映了颗粒的构象变化。VP0切割的动力学和温度依赖性进一步表明，伴随VP0切割的这种构象变化对于后续催化位点的形成是必要的。
