The tyrosyl-DNA phosphodiesterase Tdp1 is a member of the phospholipase D superfamily
The tyrosyl-DNA phosphodiesterase Tdp1 is a member of the phospholipase D superfamily
复制标题
DOI：
10.1073/pnas.211429198
复制
发表时间：
2001-10-09
影响因子：
11.1
通讯作者：
Champoux, JJ
中科院分区：
文献类型：
--
作者：
Interthal, H;Pouliott, JJ;Champoux, JJ
磷脂酶D（PLD）超家族是一组不同的蛋白质，其包括参与磷脂代谢的酶、细菌毒素、痘病毒包膜蛋白和细菌核酸酶。序列比较的基础上，我们在这里表明，酪氨酰-DNA磷酸二酯酶（Tdp 1），已牵连在修复的拓扑异构酶I共价复合物与DNA包含两个不寻常的HKD签名图案，放置在一个不同的类内的PLD超家族的酶。突变研究与人类酶中不变的组氨酸和赖氨酸的HKD基序的变化证实，这些高度保守的残基是必不可少的Tdp 1活性。此外，我们表明，像其他成员的家庭，它已被检查，该反应涉及形成一个中间体，其中裂解底物共价连接到酶。这些结果表明，由Tdp 1催化的水解反应发生的磷酰基转移化学是共同的PLD超家族的所有成员。
The phospholipase D (PLD) superfamily is a diverse group of proteins that includes enzymes involved in phospholipid metabolism, a bacterial toxin, poxvirus envelope proteins, and bacterial nucleases. Based on sequence comparisons, we show here that the tyrosyl-DNA phosphodiesterase (Tdp1) that has been implicated in the repair of topoisomerases I covalent complexes with DNA contains two unusual HKD signature motifs that place the enzyme in a distinct class within the PLD superfamily. Mutagenesis studies with the human enzyme in which the invariant histidines and lysines of the HKD motifs are changed confirm that these highly conserved residues are essential for Tdp1 activity. Furthermore, we show that, like other members of the family for which it has been examined, the reaction involves the formation of an intermediate in which the cleaved substrate is covalently linked to the enzyme. These results reveal that the hydrolytic reaction catalyzed by Tdp1 occurs by the phosphoryl transfer chemistry that is common to all members of the PLD superfamily.