Oligomeric structure of p21 ras proteins as determined by radiation inactivation.
Oligomeric structure of p21 ras proteins as determined by radiation inactivation.
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通过辐射灭活测定的 p21 ras 蛋白的寡聚结构。
DOI：
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发表时间：
1988
影响因子：
4.8
通讯作者：
E. Kempner
中科院分区：
文献类型：
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作者：
E. Santos;A. Nebreda;T. Bryan;E. Kempner
使用辐射灭活，我们确定，p21 ras蛋白表现出寡聚体的目标大小时，分析结构和功能。ras转化细胞和纯化蛋白制剂中p21的类似靶大小表明其结构是同源寡聚的。p21单体被与GTP结合活性相同的靶大小的辐射破坏，表明发生了允许单体之间能量转移的紧密缔合。在GTP、二硫苏糖醇或EDTA存在下的辐照没有改变靶大小。正常（Gly12）和转化（Lys12）形式的蛋白质表现出相似的目标大小。同源寡聚体结构表明p21 ras蛋白不符合经典G蛋白中单体α亚基的结构（α β γ异源三聚体），并与其他同源寡聚体蛋白（如大肠杆菌CRP）建立了相似性，这些蛋白在核苷酸结合后通过亚基重定向获得活性构象。
Using radiation inactivation we determined that p21 ras proteins exhibit an oligomeric target size when assayed both structurally and functionally. Similar target sizes of p21 in ras-transformed cells and in purified preparations of the protein suggested that its structure is homo-oligomeric. p21 monomers were destroyed by radiation with the same target size as the GTP binding activity, indicating the occurrence of a tight association allowing energy transfer between the monomers. Irradiation in the presence of GTP, dithiothreitol, or EDTA did not change the target size. Normal (Gly12) and transforming (Lys12) forms of the protein exhibited similar target sizes. The homo-oligomeric structure suggests that p21 ras proteins do not conform to the structure of monomeric alpha subunits in classical G proteins (alpha beta gamma heterotrimers) and establishes similarities with other homo-oligomeric proteins (such as Escherichia coli CRP) which acquire the active conformation through subunit reorientation upon nucleotide binding.