Cooperative binding of R17 coat protein to RNA.
Cooperative binding of R17 coat protein to RNA.
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DOI：
10.1021/bi00502a006
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发表时间：
1990-12
期刊：
影响因子：
2.9
通讯作者：
G. W. Witherell;H. Wu;O. Uhlenbeck
中科院分区：
文献类型：
--
作者：
G. W. Witherell;H. Wu;O. Uhlenbeck
R17外壳蛋白与含有一个或两个外壳蛋白结合位点的合成RNA的结合通过使用硝酸纤维素过滤器和凝胶保留测定来表征。RNA与两个可用的网站结合外壳蛋白在合作的方式，导致在一个更高的亲和力和降低的敏感性，pH值，离子强度，和温度相比，RNA只含有一个单一的网站。协同性可以对总体结合亲和力贡献高达~ 5 kcal/mol，其中在低pH、高离子强度和高温下发现最大协同性。相似的溶液性质的相关的fr和f2噬菌体的结合表明，协同性是由于两个外壳蛋白结合到RNA之间的有利的相互作用。因此，该系统类似于噬菌体组装的中间状态。对于含有单一位点和非特异性序列的5'或3'延伸的RNA，没有观察到协同结合，表明R17外壳蛋白具有非常低的非特异性结合亲和力。出乎意料的弱结合观察到几个RNA由于存在的替代构象状态的RNA。
The binding of the R17 coat protein to synthetic RNAs containing one or two coat protein binding sites was characterized by using nitrocellulose filter and gel-retention assays. RNAs with two available sites bound coat protein in a cooperative manner, resulting in a higher affinity and reduced sensitivity to pH, ionic strength, and temperature when compared with RNAs containing only a single site. The cooperativity can contribute up to -5 kcal/mol to the overall binding affinity with the greatest cooperativity found at low pH, high ionic strength, and high temperatures. Similar solution properties for the encapsidation of the related fr and f2 phage suggest that the cooperativity is due to favorable interactions between the two coat proteins bound to the RNA. This system therefore resembles an intermediate state of phage assembly. No cooperative binding was observed for RNAs containing a single site and a 5' or 3' extension of nonspecific sequence, indicating that R17 coat protein has a very low nonspecific binding affinity. Unexpectedly weak binding was observed for several RNAs due to the presence of alternative conformational states of the RNA.