The T4 phage SF1B helicase Dda is structurally optimized to perform DNA strand separation.
The T4 phage SF1B helicase Dda is structurally optimized to perform DNA strand separation.
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T4噬菌体SF1B解旋酶DDA在结构上优化以执行DNA链分离。
DOI：
10.1016/j.str.2012.04.013
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发表时间：
2012-07-03
期刊：
影响因子：
5.7
通讯作者：
White, Stephen W.
中科院分区：
文献类型：
--
作者：
He, Xiaoping;Byrd, Alicia K.;Yun, Mi-Kyung;Pemble, Charles W.;Harrison, David;Yeruva, Laxmi;Dahl, Christopher;Kreuzer, Kenneth N.;Raney, Kevin D.;White, Stephen W.
解旋酶通过由特征明确的解旋酶基序协调的ATP结合和水解机制在DNA上移动。然而，沿单链DNA的移位和双链DNA的链分离可能是松散耦合或紧密耦合的。Dda是一种噬菌体T4 SF1B解旋酶，与Pif1家族解旋酶具有序列同源性，它将移位与链分离紧密耦合。Dda - 单链DNA二元复合物的晶体结构揭示了一个被称为“针”的结构域，先前认为它在链分离过程中保持静止。“针”包含一个保守的苯丙氨酸，它介导一种瞬时的碱基堆积相互作用，这对于双链DNA的分离是绝对必需的。“针”通过一个延伸的SH3结构域通过蛋白质 - 蛋白质相互作用在其顶端固定，从而形成一个刚性的支柱。“针”和SH3结构域之间的保守界面为移位与链分离的紧密耦合提供了机制。
Helicases move on DNA via an ATP binding and hydrolysis mechanism coordinated by well-characterized helicase motifs. However, the translocation along ssDNA and the strand separation of dsDNA may be loosely or tightly coupled. Dda is a phage T4 SF1B helicase with sequence homology to the Pif1 family of helicases that tightly couples translocation to strand separation. The crystal structure of the Dda-ssDNA binary complex reveals a domain referred to as the ‘pin’ which was previously thought to remain static during strand separation. The pin contains a conserved phenylalanine that mediates a transient base-stacking interaction that is absolutely required for separation of dsDNA. The pin is secured at its tip by protein-protein interactions through an extended SH3 domain thereby creating a rigid strut. The conserved interface between the pin and the SH3 domain provides the mechanism for tight coupling of translocation to strand separation.
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作者：
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通讯作者：
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DOI：
10.1107/s0907444904019158
发表时间：
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