A conformational change in the helicase core is necessary but not sufficient for RNA unwinding by the DEAD box helicase YxiN.
A conformational change in the helicase core is necessary but not sufficient for RNA unwinding by the DEAD box helicase YxiN.
复制标题
解旋酶核的构象变化是必要的，但不足以用死盒解旋酶YXIN释放RNA。
DOI：
10.1093/nar/gkp397
复制
发表时间：
2009-07
影响因子：
14.9
通讯作者：
Klostermeier D
中科院分区：
文献类型：
--
作者：
Karow AR;Klostermeier D
ATP和RNA与DEAD-box解旋酶的协同结合诱导其解旋酶核心的封闭构象，并在结构域界面上广泛相互作用。结合的RNA是弯曲的，它的扭曲可能是RNA解绕的第一步。为了剖析解旋酶核心构象变化对RNA解绕的作用，我们对DEAD盒解旋酶YxiN突变体的RNA刺激的atp酶活性、RNA解绕和形成封闭构象的倾向进行了表征。缺乏ATP酶的K52Q突变体在ATP和RNA结合时形成封闭的构象，但缺乏RNA解绕。基序III的突变减慢了催化循环，但既不影响封闭构象的倾向，也不影响其整体构象。因此，解旋酶核心裂缝的闭合是必要的，但不是RNA解绕的充分条件。相反，基序V的G303A突变阻止了结构域间隙的完全闭合，影响了ATP的结合和水解，不利于解绕。可能，K52Q和motif III突变体仍然在结合RNA的主干中引入扭结，而G303A不能将RNA底物扭结。
Cooperative binding of ATP and RNA to DEAD-box helicases induces the closed conformation of their helicase core, with extensive interactions across the domain interface. The bound RNA is bent, and its distortion may constitute the first step towards RNA unwinding. To dissect the role of the conformational change in the helicase core for RNA unwinding, we characterized the RNA-stimulated ATPase activity, RNA unwinding and the propensity to form the closed conformer for mutants of the DEAD box helicase YxiN. The ATPase-deficient K52Q mutant forms a closed conformer upon binding of ATP and RNA, but is deficient in RNA unwinding. A mutation in motif III slows down the catalytic cycle, but neither affects the propensity for the closed conformer nor its global conformation. Hence, the closure of the cleft in the helicase core is necessary but not sufficient for RNA unwinding. In contrast, the G303A mutation in motif V prevents a complete closure of the inter-domain cleft, affecting ATP binding and hydrolysis and is detrimental to unwinding. Possibly, the K52Q and motif III mutants still introduce a kink into the backbone of bound RNA, whereas G303A fails to kink the RNA substrate.
登录
查看更多内容
DOI：
10.1074/jbc.c900018200
发表时间：
2009-04-17
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Collins R;Karlberg T;Lehtiö L;Schütz P;van den Berg S;Dahlgren LG;Hammarström M;Weigelt J;Schüler H
通讯作者：
Schüler H
影响因子：
5.3
作者：
PAUSE, A;METHOT, N;SONENBERG, N
通讯作者：
SONENBERG, N
影响因子：
4.5
作者：
Cheng, ZH;Coller, J;Song, H
通讯作者：
Song, H
影响因子：
5.6
作者：
Kossen, K;Karginov, FV;Uhlenbeck, OC
通讯作者：
Uhlenbeck, OC
DOI：
10.1073/pnas.0811115106
发表时间：
2008-12-23
影响因子：
11.1
作者：
Liu, Fei;Putnam, Andrea;Jankowsky, Eckhard
通讯作者：
Jankowsky, Eckhard