The Acidic C-terminal Tail of the GyrA Subunit Moderates the DNA Supercoiling Activity of Bacillus subtilis Gyrase
The Acidic C-terminal Tail of the GyrA Subunit Moderates the DNA Supercoiling Activity of Bacillus subtilis Gyrase
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DOI：
10.1074/jbc.m114.547745
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发表时间：
2014-05-02
影响因子：
4.8
通讯作者：
Klostermeier, Dagmar
中科院分区：
文献类型：
--
作者：
Lanz, Martin A.;Farhat, Mohamad;Klostermeier, Dagmar
背景：DNA旋转酶催化ATP依赖的负性DNA超螺旋。结果：缺失酸性C-末端尾部导致B更强的DNA弯曲。枯草杆菌促旋酶C末端结构域和加速DNA刺激的ATP酶和促旋酶的超螺旋活性。结论：C尾下调B的负性超螺旋。枯草促旋酶重要性：C-tail是一个多功能元件，可以不同程度地调节不同促旋酶的活性。促旋酶是一种II型DNA拓扑异构酶，在ATP依赖的反应中将负超螺旋引入DNA。它由两个GyrA亚基的N-末端结构域和两个GyrB亚基形成的拓扑异构酶核心组成，催化双链DNA切割和第二个双链DNA通过第一个中的差距。GyrA亚基的C-末端结构域（CTD）形成α-风车并围绕其带正电荷的周边结合DNA。结果，DNA作为正超螺旋结合，其通过链通道转化为负超螺旋。CTD包含一个保守的7-氨基酸基序，连接叶片1和6的风车，是一个标志性的特征的旋转酶。这种所谓的GyrA盒的缺失消除了由CTD和DNA诱导的N门变窄引起的DNA弯曲，影响T段呈递，减少DNA结合ATP水解的偶联，并导致超螺旋缺陷。最近，大肠杆菌促旋酶的超螺旋活性的严重损失后，删除非保守的酸性C-末端尾（C-尾）的CTD已被报道。我们在这里表明，与E。在大肠杆菌促旋酶中，C-尾是枯草芽孢杆菌促旋酶活性的非常温和的负调节剂。C-尾降低了CTD引起的DNA弯曲程度，但对DNA诱导的螺旋酶构象变化没有影响，螺旋酶构象变化先于链通过，并且仅降低了DNA刺激的ATP酶和DNA超螺旋活性2倍。我们的研究结果与物种特异性，不同的调节作用的C-尾在不同的生物体的回旋酶。
Background: DNA gyrase catalyzes ATP-dependent negative DNA supercoiling. Results: Deletion of the acidic C-terminal tail causes stronger DNA bending by the B. subtilis gyrase C-terminal domains and accelerated DNA-stimulated ATPase and supercoiling activities of gyrase. Conclusion: The C-tail down-regulates negative supercoiling by B. subtilis gyrase. Significance: The C-tail is a versatile element that differentially regulates the activity of different gyrases.Gyrase is a type II DNA topoisomerase that introduces negative supercoils into DNA in an ATP-dependent reaction. It consists of a topoisomerase core, formed by the N-terminal domains of the two GyrA subunits and by the two GyrB subunits, that catalyzes double-stranded DNA cleavage and passage of a second double-stranded DNA through the gap in the first. The C-terminal domains (CTDs) of the GyrA subunits form a -pinwheel and bind DNA around their positively charged perimeter. As a result, DNA is bound as a positive supercoil that is converted into a negative supercoil by strand passage. The CTDs contain a conserved 7-amino acid motif that connects blades 1 and 6 of the -pinwheel and is a hallmark feature of gyrases. Deletion of this so-called GyrA-box abrogates DNA bending by the CTDs and DNA-induced narrowing of the N-gate, affects T-segment presentation, reduces the coupling of DNA binding to ATP hydrolysis, and leads to supercoiling deficiency. Recently, a severe loss of supercoiling activity of Escherichia coli gyrase upon deletion of the non-conserved acidic C-terminal tail (C-tail) of the CTDs has been reported. We show here that, in contrast to E. coli gyrase, the C-tail is a very moderate negative regulator of Bacillus subtilis gyrase activity. The C-tail reduces the degree of DNA bending by the CTDs but has no effect on DNA-induced conformational changes of gyrase that precede strand passage and reduces DNA-stimulated ATPase and DNA supercoiling activities only 2-fold. Our results are in agreement with species-specific, differential regulatory effects of the C-tail in gyrases from different organisms.