Co(ll)-detection does not follow Kco(ll) gradient: channelling in Co(ll)-sensing.
Co(ll)-detection does not follow Kco(ll) gradient: channelling in Co(ll)-sensing.
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Co(II)-检测不遵循Kco(II)梯度：Co(II)-传感中的通道。
DOI：
10.1039/c3mt20241k
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Patterson CJ
中科院分区：
文献类型：
--
作者：
Patterson CJ
MerR样转录激活因子CoaR检测过剩的钴（ii），以调节钴（ii）外排在蓝藻。这种生物体还具有来自以Zn（ii）-传感器ZiaR和Zur加Ni（ii）-传感器InrS为代表的另外三个家族的细胞溶质金属传感器。通过与Fura-2的竞争，我们发现CoaR的KCo（II）小于7 × 10− 8 M，比ZiaR、Zur和InrS弱（KCo（II）分别为6.94 ± 1.3 × 10− 10 M、4.56 ± 0.16 × 10− 10 M和7.69 ± 1.1 × 10− 9 M）。此外，钴（ii）促进DNA的解离ZiaR和DNA的协会，通过在体外的方式类似于锌（ii），监测荧光各向异性。在暴露于最大非抑制性[Co（ii）] 48小时后，两种Zn（ii）-传感器体内的CoaR响应没有，尽管它们的更紧密的KCo（II）和尽管Co（ii）在体外触发ZiaR和ZiaR中的变构。这些数据意味着两个Zn（ii）传感器未能响应，因为它们在这些条件下无法获得Co（ii）。CoaR与维生素B12生物合成酶前啡肽异构酶（precorrin isomerase）具有序列相似性，是一种膜结合型结构域。此外，定点诱变揭示了转录激活需要预测与四吡咯形成氢键的CoaR残基。钴（ii）需要维生素B12的生物合成途径也是膜相关的建议推定的机制，其中钴（ii）含四吡咯和/或钴（ii）离子被引导到CoaR。
The MerR-like transcriptional activator CoaR detects surplus Co(ii) to regulate Co(ii) efflux in a cyanobacterium. This organism also has cytosolic metal-sensors from three further families represented by Zn(ii)-sensors ZiaR and Zur plus Ni(ii)-sensor InrS. Here we discover by competition with Fura-2 that CoaR hasKCo(II)weaker than 7 × 10−8M, which is weaker than ZiaR, Zur and InrS (KCo(II)= 6.94 ± 1.3 × 10−10M; 4.56 ± 0.16 × 10−10M; and 7.69 ± 1.1 × 10−9M respectively).KCo(II)for CoaR is also weak in the CoaR–DNA adduct. Further, Co(ii) promotes DNA-dissociation by ZiaR and DNA-association by Zurin vitroin a manner analogous to Zn(ii), as monitored by fluorescence anisotropy. After 48 h exposure to maximum non-inhibitory [Co(ii)], CoaR respondsin vivoyet the two Zn(ii)-sensors do not, despite their tighterKCo(II)and despite Co(ii) triggering allostery in ZiaR and Zurin vitro. These data imply that the two Zn(ii) sensors fail to respond because they fail to gain access to Co(ii) under these conditionsin vivo. Several lines of evidence suggest that CoaR is membrane associatedviaa domain with sequence similarity to precorrin isomerase, an enzyme of vitamin B12biosynthesis. Moreover, site directed mutagenesis reveals that transcriptional activation requires CoaR residues that are predicted to form hydrogen bonds to a tetrapyrrole. The Co(ii)-requiring vitamin B12biosynthetic pathway is also membrane associated suggesting putative mechanisms by which Co(ii)-containing tetrapyrroles and/or Co(ii) ions are channelled to CoaR.
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DOI：
10.1002/j.1460-2075.1993.tb05673.x
发表时间：
1993-02
期刊：
The EMBO Journal
影响因子：
--
作者：
Julian Parkhill;A. Ansari;Jeffrey G. Wright;N. Brown;T. O’Halloran
通讯作者：
Julian Parkhill;A. Ansari;Jeffrey G. Wright;N. Brown;T. O’Halloran
影响因子：
15
作者：
Iwig, Jeffrey S.;Leitch, Sharon;Chivers, Peter T.
通讯作者：
Chivers, Peter T.
影响因子：
4.8
作者：
Rutherford, JC;Cavet, JS;Robinson, NJ
通讯作者：
Robinson, NJ
DOI：
10.1073/pnas.89.16.7576
发表时间：
1992
影响因子：
11.1
作者：
Schmitt,MP;Twiddy,EM;Holmes,RK
通讯作者：
Holmes,RK
影响因子：
5.4
作者：
Hoffmann, Doerte;Gutekunst, Kirstin;Appel, Jens
通讯作者：
Appel, Jens