Structure, mechanism, and specificity of a eukaryal tRNA restriction enzyme involved in self-nonself discrimination.
Structure, mechanism, and specificity of a eukaryal tRNA restriction enzyme involved in self-nonself discrimination.
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DOI：
10.1016/j.celrep.2014.03.034
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发表时间：
2014-04-24
期刊：
影响因子：
8.8
通讯作者：
Shuman S
中科院分区：
文献类型：
--
作者：
Chakravarty AK;Smith P;Jalan R;Shuman S
反密码子核酸酶对tRNA的限制是细胞应激反应和自我-非自我辨别的基础。反密码子断裂抑制蛋白质合成，这反过来导致生长停滞或细胞死亡。由刺槐毕赤酵母（Pichia acaciae）加工的真核核糖毒素PaT通过切割tRNAGln（UUG）来抑制酿酒酵母的生长。我们发现，重组PaT切割合成tRNAGln（UUG）茎环RNA通过酯交换在一个单一的网站3′的摆动尿苷，产生2′，3 ′-环磷酸和5′-OH结束。用腺嘌呤或鸟嘌呤取代摆动的核碱基可以抑制切割。我们报告的晶体结构的PaT，它揭示了一个新的折叠和活性位点，其中的基本成分是照亮诱变。刺槐毕赤酵母通过一种独特的细胞内免疫蛋白ImmPaT来逃避自身毒性，ImmPaT结合PaT并消除核酸酶活性。我们的研究结果突出了tRNA限制和免疫系统的进化多样性。
tRNA restriction by anticodon nucleases underlies cellular stress responses and self-nonself discrimination in a wide range of taxa. Anticodon breakage inhibits protein synthesis, which in turn results in growth arrest or cell death. The eukaryal ribotoxin PaT elaborated by Pichia acaciae inhibits growth of Saccharomyces cerevisiae via cleavage of tRNAGln(UUG). We find that recombinant PaT incises a synthetic tRNAGln(UUG) stem-loop RNA by transesterification at a single site 3′ of the wobble uridine, yielding 2′,3′-cyclic phosphate and 5′-OH ends. Incision is suppressed by replacing the wobble nucleobase with adenine or guanine. We report the crystal structure of PaT, which unveils a novel fold and active site, essential constituents of which are illuminated by mutagenesis. Pichia acaciae evades self toxicity via a distinctive intracellular immunity protein, ImmPaT, which binds PaT and effaces nuclease activity. Our results highlight the evolutionary diversity of tRNA restriction and immunity systems.
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影响因子：
5
作者：
Ardelt, Wojciech;Ardelt, Barbara;Darzynkiewicz, Zbigniew
通讯作者：
Darzynkiewicz, Zbigniew
影响因子：
4.5
作者：
Keppetipola, Niroshika;Jain, Ruchi;Shuman, Stewart
通讯作者：
Shuman, Stewart
影响因子：
14.9
作者：
Lu J;Esberg A;Huang B;Byström AS
通讯作者：
Byström AS
影响因子：
64.5
作者：
Thompson, Debrah M.;Parker, Roy
通讯作者：
Parker, Roy
DOI：
10.1073/pnas.140213797
发表时间：
2000-07-18
影响因子：
11.1
作者：
Tomita, K;Ogawa, T;Masaki, H
通讯作者：
Masaki, H