Acetylation of Lysine 243 Inhibits the oriC Binding Ability of DnaA in Escherichia coli.
Acetylation of Lysine 243 Inhibits the oriC Binding Ability of DnaA in Escherichia coli.
复制标题
赖氨酸 243 的乙酰化抑制大肠杆菌中 DnaA 的 oriC 结合能力
DOI：
10.3389/fmicb.2017.00699
复制
发表时间：
2017
影响因子：
5.2
通讯作者：
Yao YF
中科院分区：
文献类型：
--
作者：
Li S;Zhang Q;Xu Z;Yao YF
DNA复制起始是细胞周期的中心事件，受到多种调控机制的严格控制。我们之前的研究表明，残基赖氨酸(K) 178的乙酰化可以阻止DNA与ATP结合，从而抑制DNA的复制起始。在这里，我们发现另一个残基K243对dna在体内的充分活性至关重要。K243可被乙酰化，其乙酰化水平随细胞生长而变化。一种含有N？-acetyllysine at K243 （K243Ac）保留了ATP/ADP的结合能力，但对oriC区的结合活性降低。dna酶I足迹分析显示，DnaA K243Ac不能识别dna盒I3、C1和C3，因此，它与oriC形成了一个不完整的起始复合物。最后，我们发现乙酰磷酸和去乙酰化酶CobB可以调节体内K243的乙酰化水平。这些发现表明，DNA K243乙酰化干扰了其与低亲和力DNA盒子的结合，并为DNA复制起始的调控机制提供了新的见解。
DNA replication initiation is a central event in the cell cycle, and it is strictly controlled by multiple regulatory mechanisms. Our previous work showed that acetylation of residue lysine (K) 178 prevents DnaA from binding to ATP, which leads to the inhibition of DNA replication initiation. Here, we show that another residue, K243, is critical for DnaA full activity in vivo. K243 can be acetylated, and its acetylation level varies with cell growth. A homogeneous, recombinant DnaA that contains N?-acetyllysine at K243 (K243Ac) retained its ATP/ADP binding ability, but showed decreased binding activity to the oriC region. A DNase I footprinting assay showed that DnaA K243Ac failed to recognize DnaA boxes I3, C1, and C3, and, thus, it formed an incomplete initiation complex with oriC. Finally, we found that acetyl phosphate and the deacetylase CobB can regulate the acetylation level of K243 in vivo. These findings suggest that DnaA K243 acetylation disturbs its binding to low-affinity DnaA boxes, and they provide new insights into the regulatory mechanisms of DNA replication initiation.