Do yeast aminoacyl-tRNA synthetases exist as soluble enzymes within the cytoplasm?
Do yeast aminoacyl-tRNA synthetases exist as soluble enzymes within the cytoplasm?
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酵母氨酰-tRNA 合成酶是否作为可溶性酶存在于细胞质中？
DOI：
10.1111/j.1432-1033.1985.tb08933.x
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
J. Waller
中科院分区：
文献类型：
--
作者：
B. Çirakoğlu;J. Waller
从酵母菌粗提物中提取的氨基酰基trna合成酶通过离子相互作用与肝素-超凝胶结合，而大肠杆菌中提取的相应酶则不能。从酵母和大肠杆菌中纯化的赖氨酸- trna合成酶的行为进行了详细的研究。来自酵母的天然二聚体酶（Mr 2 X 73000）与固定化肝素或tRNA以及带负电荷的脂质体强烈相互作用，而来自大肠杆菌的相应天然酶（Mr 2 X 65000）对这些载体没有亲和力。此外，酵母的天然酶与多阴离子载体相互作用的能力在蛋白水解转化为mr2 X 65500的完全活性修饰二聚体时失去了。提出了一种结构模型，根据该模型，酵母赖氨酸- trna合成酶的每个亚基都由一个与原核酶大小相似的功能结构域组成，毗邻一个负责与带负电荷的载体结合的“结合”结构域。低等真核生物氨基酰基- trna合成酶在进化过程中获得了这种特性，这表明它在体内具有重要的功能，与催化无关。我们提出，它促进细胞质内这些酶的区室化，通过与尚未确定的，带负电荷的成分的关联，通过静电相互作用太脆弱，无法承受通常的提取条件。
The aminoacyl-tRNA synthetases from a crude extract of yeast were shown to bind to heparin-Ultrogel through ionic interactions, in conditions where the corresponding enzymes from Escherichia coli did not. The behaviour of purified lysyl-tRNA synthetases from yeast and E. coli was examined in detail. The native dimeric enzyme from yeast (Mr 2 X 73000) strongly interacted with immobilized heparin or tRNA, as well as with negatively charged liposomes, in conditions where the corresponding native enzyme from E. coli (Mr 2 X 65000) displayed no affinity for these supports. Moreover, the aptitude of the native enzyme from yeast to interact with polyanionic carriers was lost on proteolytic conversion to a fully active modified dimer of Mr 2 X 65500. A structural model is proposed, according to which each subunit of yeast lysyl-tRNA synthetase is composed of a functional domain similar in size to that of the prokaryotic enzyme, contiguous to a 'binding' domain responsible for association to negatively charged carriers. The evolutionary acquisition of this property by lower eukaryotic aminoacyl-tRNA synthetases suggests that it fulfils an important function in vivo, unrelated to catalysis. We propose that it promotes the compartmentalization of these enzymes within the cytoplasm, through associations with as yet unidentified, negatively charged components, by electrostatic interactions too fragile to withstand the usual extraction conditions.
蛋白质溶液碘化后快速去除[125I]碘化物的方法。
影响因子：
2.9
作者：
Tuszynski,GP;Knight,L;Piperno,JR;Walsh,PN
通讯作者：
Walsh,PN