NUCLEATION AND GROWTH PHASES IN THE POLYMERIZATION OF COAT AND SCAFFOLDING SUBUNITS INTO ICOSAHEDRAL PROCAPSID SHELLS
NUCLEATION AND GROWTH PHASES IN THE POLYMERIZATION OF COAT AND SCAFFOLDING SUBUNITS INTO ICOSAHEDRAL PROCAPSID SHELLS
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DOI：
10.1016/s0006-3495(93)81443-7
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发表时间：
1993-03-01
影响因子：
3.4
通讯作者：
KING, J
中科院分区：
文献类型：
--
作者：
PREVELIGE, PE;THOMAS, D;KING, J
蛋白质亚基聚合成没有DNA的前体外壳是双链DNA病毒组装的关键过程。对于噬菌体P22的二十面体前衣壳，外壳和支架蛋白亚基不单独组装，但混合后，在体外共聚成双壳前衣壳。聚合反应显示成核限制反应的特征：缺乏中间组装状态、临界浓度和显示滞后期的动力学。部分形成的壳中间体在生长阶段通过反应混合物的电子显微镜直接可视化。这些中间体的形态表明，组装是一个高度定向的过程。该反应的初始速率取决于外壳亚基浓度的五次方和支架浓度的二次方或三次方，这表明外壳蛋白的五聚体和支架蛋白的二聚体或三聚体分别参与限速步骤。
The polymerization of protein subunits into precursor shells empty of DNA is a critical process in the assembly of double-stranded DNA viruses. For the well-characterized icosahedral procapsid of phage P22, coat and scaffolding protein subunits do not assemble separately but, upon mixing, copolymerize into double-shelled procapsids in vitro. The polymerization reaction displays the characteristics of a nucleation limited reaction: a paucity of intermediate assembly states, a critical concentration, and kinetics displaying a lag phase. Partially formed shell intermediates were directly visualized during the growth phase by electron microscopy of the reaction mixture. The morphology of these intermediates suggests that assembly is a highly directed process. The initial rate of this reaction depends on the fifth power of the coat subunit concentration and the second or third power of the scaffolding concentration, suggesting that pentamer of coat protein and dimers or trimers of scaffolding protein, respectively, participate in the rate-limiting step.