Differential heterocyclic substrate recognition by, and pteridine inhibition of E. coli and human tRNA-guanine transglycosylases.
Differential heterocyclic substrate recognition by, and pteridine inhibition of E. coli and human tRNA-guanine transglycosylases.
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DOI：
10.1016/j.bbrc.2011.05.100
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发表时间：
2011-06-24
影响因子：
3.1
通讯作者：
Garcia, George A.
中科院分区：
文献类型：
--
作者：
Thomas, C. Eric;Chen, Yi-Chen;Garcia, George A.
tRNA-鸟嘌呤转糖基酶（TGT）负责将7-脱氮鸟嘌呤修饰的碱基整合到真细菌（preQ 1）、真核生物（rekarya）和古细菌（preQ 0）中的某些tRNA中。在每个王国中，特定的修饰基是不同的。我们已经发现真细菌和真核生物的TGTs已经进化到对其同源杂环碱基相当特异，并且Cys 145（E.大肠杆菌）在识别preQl的氨基甲基侧链中是重要的（Chen等人（2011）Nuc. Acids Res.39，2834）。对E. coliTGT已经被构建来探测其他三个活性位点氨基酸在杂环底物的差异识别中的作用。这些突变体也被用来探测大肠杆菌的差异抑制。大肠杆菌与人TGT的比较。结果表明，这些活性位点氨基酸的突变可以“打开”活性位点，允许竞争性蝶啶抑制剂的结合。然而，即使是这些突变体中的“最佳”突变体在高达50 μM的浓度下仍然不能识别精氨酸，这表明其他变化对于适应真细菌TGT将精氨酸掺入RNA是必要的。蝶啶抑制结果与早期的假设一致，即蝶啶可能调节真核TGT活性
tRNA-guanine transglycosylases (TGTs) are responsible for incorporating 7-deazaguanine-modified bases into certain tRNAs in eubacteria (preQ1), eukarya (queuine) and archaea (preQ0). In each kingdom, the specific modified base is different. We have found that the eubacterial and eukaryal TGTs have evolved to be quite specific for their cognate heterocyclic base and that Cys145 (E. coli) is important in recognizing the amino methyl side chain of preQ1 (Chen et al. (2011) Nuc. Acids Res.39, 2834). A series of mutants of the E. coli TGT have been constructed to probe the role of three other active site amino acids in the differential recognition of heterocyclic substrates. These mutants have also been used to probe the differential inhibition of E. coli versus human TGTs by pteridines. The results indicate that mutation of these active site amino acids can “open up” the active site, allowing for the binding of competitive pteridine inhibitors. However, even the “best” of these mutants still does not recognize queuine at concentrations up to 50 μM, suggesting that other changes are necessary to adapt the eubacterial TGT to incorporate queuine into RNA. The pteridine inhibition results are consistent with an earlier hypothesis that pteridines may regulate eukaryal TGT activity
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影响因子：
14.9
作者：
Chen YC;Brooks AF;Goodenough-Lashua DM;Kittendorf JD;Showalter HD;Garcia GA
通讯作者：
Garcia GA
影响因子：
14.9
作者：
KUCHINO, Y;KASAI, H;NISHIMURA, S
通讯作者：
NISHIMURA, S
影响因子：
3.2
作者：
Phillips, Gabriella;El Yacoubi, Basma;de Crecy-Lagard, Valerie
通讯作者：
de Crecy-Lagard, Valerie
影响因子：
5.1
作者：
Goodenough-Lashua, DM;Garcia, GA
通讯作者：
Garcia, GA
影响因子：
2.9
作者：
HOOPS, GC;TOWNSEND, LB;GARCIA, GA
通讯作者：
GARCIA, GA