Terminal DNA structure and ATP influence binding parameters of the DNA-dependent protein kinase at an early step prior to DNA synapsis.
Terminal DNA structure and ATP influence binding parameters of the DNA-dependent protein kinase at an early step prior to DNA synapsis.
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DOI：
10.1093/nar/gkj504
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发表时间：
2006
影响因子：
14.9
通讯作者：
Dynan, WS
中科院分区：
文献类型：
--
作者：
Jovanovic, M;Dynan, WS
DNA依赖性蛋白激酶催化亚基（DNA-PKcs）调控哺乳动物细胞DNA双链断裂修复的非同源末端连接途径。DNA-PKcs感知和响应不同末端DNA结构的能力被认为对其调节功能很重要。目前还不清楚是否歧视发生在最初的蛋白质-DNA复合物的形成时，或稍后，在形成配对时，或相反的DNA末端之间的突触复合物。为了进一步了解调控机制，我们表征了DNA-PKcs与不能进行突触的固定化DNA片段的结合。结果表明，DNA-PKcs强烈区分不同的终端结构在最初的复合物形成的时间。尽管Ku蛋白总体上稳定DNA-PKcs结合，但它不是区分末端结构所必需的。碱基错配、温度和链间连接的存在以表明需要DNA解旋的方式影响初始复合物的稳定性，这让人想起RNA聚合酶-启动子DNA相互作用的“开放复合物”模型。ATP和不可水解的ATP类似物也影响DNA-PKcs·DNA复合物的稳定性，显然是通过不需要DNA-PKcs自磷酸化的变构机制。
The DNA-dependent protein kinase catalytic subunit (DNA-PKcs) regulates the non-homologous end-joining pathway of DNA double-strand break repair in mammalian cells. The ability of DNA-PKcs to sense and respond to different terminal DNA structures is postulated to be important for its regulatory function. It is unclear whether discrimination occurs at the time of formation of the initial protein–DNA complex or later, at the time of formation of a paired, or synaptic complex between opposing DNA ends. To gain further insight into the mechanism of regulation, we characterized the binding of DNA-PKcs to immobilized DNA fragments that cannot undergo synapsis. Results showed that DNA-PKcs strongly discriminates between different terminal structures at the time of initial complex formation. Although Ku protein stabilizes DNA-PKcs binding overall, it is not required for discrimination between terminal structures. Base mispairing, temperature and the presence of an interstrand linkage influence the stability of the initial complex in a manner that suggests a requirement for DNA unwinding, reminiscent of the ‘open complex’ model of RNA polymerase–promoter DNA interaction. ATP and a nonhydrolyzable ATP analog also influence the stability of the DNA-PKcs•DNA complex, apparently by an allosteric mechanism that does not require DNA-PKcs autophosphorylation.
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影响因子：
4.8
作者：
Chan, DW;LeesMiller, SP
通讯作者：
LeesMiller, SP
影响因子：
5.3
作者：
Ding, Q;Reddy, YVR;Meek, K
通讯作者：
Meek, K
影响因子：
14.9
作者：
Block, WD;Yu, YP;Lees-Miller, SP
通讯作者：
Lees-Miller, SP
DOI：
10.1073/pnas.95.2.525
发表时间：
1998-01-20
影响因子：
11.1
作者：
Hammarsten, O;Chu, G
通讯作者：
Chu, G
影响因子：
3.8
作者：
Lee, KJ;Jovanovic, M;Dynan, WS
通讯作者：
Dynan, WS