Tagetitoxin inhibits transcription by stabilizing pre-translocated state of the elongation complex.
Tagetitoxin inhibits transcription by stabilizing pre-translocated state of the elongation complex.
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DOI：
10.1093/nar/gkt708
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发表时间：
2013-11
影响因子：
14.9
通讯作者：
Zenkin N
中科院分区：
文献类型：
--
作者：
Yuzenkova Y;Roghanian M;Bochkareva A;Zenkin N
转录延伸包括核苷酸加成循环的重复：磷酸二酯键的形成、转位和下一个核苷酸的结合。多亚基RNA聚合酶毒素(TGT)的抑制剂以一种神秘的方式减缓核苷酸的添加，这种方式依赖于序列，只在模板的某些位置。在这里，我们证明了TGT既不影响RNA合成的化学，也不诱导后向易位，也不与活性中心的核苷三磷酸(NTP)竞争。相反，TGT增加了延伸复合体的预移位状态的稳定性，从而减缓了以下核苷酸的添加。我们表明，抑制的程度直接取决于预位移态的内在稳定性。转位平衡对转录序列的依赖导致了TGT在模板不同位置的抑制作用的广泛分布(∼1-103倍)，从而解释了TGT作用的序列特异性。我们提供的生化证据表明，在预移位状态下，TGT稳定了触发环的折叠构象，从而抑制了复合体的向前和向后移位。结果表明，触发器环在预移位状态下的折叠可能有助于减少伸长复合体的回溯。总体而言，我们认为易位可能是RNA合成的一个限制和高度调控的步骤。
Transcription elongation consists of repetition of the nucleotide addition cycle: phosphodiester bond formation, translocation and binding of the next nucleotide. Inhibitor of multi-subunit RNA polymerase tagetitoxin (TGT) enigmatically slows down addition of nucleotides in a sequence-dependent manner, only at certain positions of the template. Here, we show that TGT neither affects chemistry of RNA synthesis nor induces backward translocation, nor competes with the nucleoside triphosphate (NTP) in the active center. Instead, TGT increases the stability of the pre-translocated state of elongation complex, thus slowing down addition of the following nucleotide. We show that the extent of inhibition directly depends on the intrinsic stability of the pre-translocated state. The dependence of translocation equilibrium on the transcribed sequence results in a wide distribution (∼1–103-fold) of inhibitory effects of TGT at different positions of the template, thus explaining sequence-specificity of TGT action. We provide biochemical evidence that, in pre-translocated state, TGT stabilizes folded conformation of the Trigger Loop, which inhibits forward and backward translocation of the complex. The results suggest that Trigger Loop folding in the pre-translocated state may serve to reduce backtracking of the elongation complex. Overall, we propose that translocation may be a limiting and highly regulated step of RNA synthesis.
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影响因子：
14.9
作者：
Roghanian M;Yuzenkova Y;Zenkin N
通讯作者：
Zenkin N
影响因子：
11.4
作者：
Bochkareva, Aleksandra;Yuzenkova, Yulia;Tadigotla, Vasisht R.;Zenkin, Nikolay
通讯作者：
Zenkin, Nikolay
影响因子：
14.9
作者：
Malinen AM;Turtola M;Parthiban M;Vainonen L;Johnson MS;Belogurov GA
通讯作者：
Belogurov GA
影响因子：
56.9
作者：
Zenkin, Nikolay;Yuzenkova, Yulia;Severinov, Konstantin
通讯作者：
Severinov, Konstantin
将RNA聚合酶回溯与大肠杆菌中的基因组不稳定性联系起来。
影响因子：
64.5
作者：
Dutta D;Shatalin K;Epshtein V;Gottesman ME;Nudler E
通讯作者：
Nudler E