Impact of the K24N mutation on the transactivation domain of p53 and its binding to murine double-minute clone 2.
Impact of the K24N mutation on the transactivation domain of p53 and its binding to murine double-minute clone 2.
复制标题
K24N 突变对 p53 反式激活结构域及其与鼠双分钟克隆 2 结合的影响。
DOI：
10.1002/prot.24310
复制
发表时间：
2013
期刊：
影响因子：
2.9
通讯作者：
Ytreberg,FMarty
中科院分区：
文献类型：
--
作者：
Zhan,YingqianAda;Wu,Hongwei;Powell,AnneT;Daughdrill,GaryW;Ytreberg,FMarty
p53 转录因子的水平受到 E3 泛素连接酶鼠双分钟克隆 2 (MDM2) 的负调节。 p53 和 MDM2 之间的相互作用对于维持大多数真核生物的基因组完整性至关重要。先前的结构研究表明，MDM2 与 p53 反式激活结构域 (p53TAD) 的残基 17 至 29 结合。p53TAD 的 K24N 突变将位置 24 的赖氨酸更改为天冬酰胺。这种突变自然发生在牛科动物中，也存在于一种罕见的人类妊娠癌绒毛膜癌中。在这项研究中，我们研究了 K24N 突变如何影响 p53TAD 与 MDM2 结合的亲和力、结构和动力学。 p53TAD 的核磁共振研究表明，K24N 突变体比野生型更灵活，并且具有更少的瞬时螺旋二级结构。等温滴定量热法测量表明，结构和动力学的这些变化不会显着改变 p53TAD-MDM2 的结合亲和力。最后，自由能扰动和标准分子动力学模拟表明，可忽略的亲和力变化是由于 K24N 突变体和 MDM2 结合时之间的补偿相互作用能所致。总体而言，数据表明 K24N-MDM2 复合物能够至少部分补偿未结合 K24N 中构象熵的增加以及结合态静电相互作用能的增加。
The level of the p53 transcription factor is negatively regulated by the E3 ubiguitin ligase murine double minute clone 2 (MDM2). The interaction between p53 and MDM2 is essential for the maintenance of genomic integrity for most eukaryotes. Previous structural studies revealed that MDM2 binds to p53 transactivation domain (p53TAD) from residues 17 to 29. The K24N mutation of p53TAD changes a lysine at position 24 to an asparagine. This mutation occurs naturally in the bovine family and is also found in a rare form of human gestational cancer called choriocarcinoma. In this study we have investigated how the K24N mutation affects the affinity, structure, and dynamics of p53TAD binding to MDM2. Nuclear magnetic resonance studies of p53TAD show the K24N mutant is more flexible and has less transient helical secondary structure than the wildtype. Isothermal titration calorimetry measurements demonstrate that these changes in structure and dynamics do not significantly change the binding affinity for p53TAD-MDM2. Finally, free energy perturbation and standard molecular dynamics simulations suggest the negligible affinity change is due to a compensating interaction energy between the K24N mutant and MDM2 when it is bound. Overall, the data suggests that the K24N-MDM2 complex is able to at least partly compensate for an increase in the conformational entropy in unbound K24N with an increase in the bound state electrostatic interaction energy.