Distinct GDP/GTP bound states of the tandem G-domains of EngA regulate ribosome binding.
Distinct GDP/GTP bound states of the tandem G-domains of EngA regulate ribosome binding.
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DOI：
10.1093/nar/gkp107
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发表时间：
2009-04
影响因子：
14.9
通讯作者：
Prakash B
中科院分区：
文献类型：
--
作者：
Tomar SK;Dhimole N;Chatterjee M;Prakash B
EngA是一种独特的GTPase，它包含一个kh结构域和两个连续的g结构域，具有独特的核苷酸结合和水解活性。到目前为止，有报道称大肠杆菌EngA以鸟苷-5 ' -三磷酸（GTP）结合状态结合50S核糖体亚基。在这里，我们首次使用允许分离两个g结构域GD1和GD2活性的突变，我们表明除了50S， EngA还结合30S和70S亚基。我们发现任何enga -核糖体结合的关键要求是GTP与GD2的结合。在这种状态下，EngA表现出弱的50S关联，当GD1也结合GTP时，这种关联进一步稳定。GTP与鸟苷-5′-二磷酸（GDP）在GD1处交换，导致与50S， 30S和70S相互作用。因此，GD1似乎通过GTP水解来调节EngA对单独的50S或对50S、30S和70S亚基的差异特异性。此外，通过使用缺少GD1或缺少GD1和GD2的构建体，我们推断GD1在与GTP和GDP结合时采用不同的构象来掩盖或揭露EngA上的30S结合位点。我们的结果提出了一个模型，其中两个g结构域的不同核苷酸结合状态调节特定enga -核糖体复合物的形成。
EngA, a unique GTPase containing a KH-domain preceded by two consecutive G-domains, displays distinct nucleotide binding and hydrolysis activities. So far, Escherichia coli EngA is reported to bind the 50S ribosomal subunit in the guanosine-5′-trihosphate (GTP) bound state. Here, for the first time, using mutations that allow isolating the activities of the two G-domains, GD1 and GD2, we show that apart from 50S, EngA also binds the 30S and 70S subunits. We identify that the key requirement for any EngA–ribosome association is GTP binding to GD2. In this state, EngA displays a weak 50S association, which is further stabilized when GD1 too binds GTP. Exchanging bound GTP with guanosine-5′-diphosphate (GDP), at GD1, results in interactions with 50S, 30S and 70S. Therefore, it appears that GD1 employs GTP hydrolysis as a means to regulate the differential specificity of EngA to either 50S alone or to 50S, 30S and 70S subunits. Furthermore, using constructs lacking either GD1 or both GD1 and GD2, we infer that GD1, when bound to GTP and GDP, adopts distinct conformations to mask or unmask the 30S binding site on EngA. Our results suggest a model where distinct nucleotide-bound states of the two G-domains regulate formation of specific EngA–ribosome complexes.
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影响因子：
3.2
作者：
Daigle, DM;Brown, ED
通讯作者：
Brown, ED
在存在核苷酸的情况下，大肠杆菌HFLX与50S核糖体亚基相互作用。
DOI：
10.1016/j.bbrc.2008.12.072
发表时间：
2009-02-06
影响因子：
3.1
作者：
Jain, Nikhil;Dhimole, Neha;Khan, Abu Rafay;De, Debojyoti;Tomar, Sushil Kumar;Sajish, Mathew;Dutta, Dipak;Parrack, Pradeep;Prakash, Balaji
通讯作者：
Prakash, Balaji
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
3.2
作者：
Tan, J;Jakob, U;Bardwell, JCA
通讯作者：
Bardwell, JCA
DOI：
10.1046/j.1432-1033.2001.02493.x
发表时间：
2001-11-01
期刊：
EUROPEAN JOURNAL OF BIOCHEMISTRY
影响因子：
--
作者：
Hang, JQ;Meier, TI;Zhao, G
通讯作者：
Zhao, G