AMINOACYL-TRANSFER-RNA SYNTHETASES FROM BAKERS-YEAST - REACTING SITE OF ENZYMATIC AMINOACYLATION IS NOT UNIFORM FOR ALL TRANSFER-RNA
AMINOACYL-TRANSFER-RNA SYNTHETASES FROM BAKERS-YEAST - REACTING SITE OF ENZYMATIC AMINOACYLATION IS NOT UNIFORM FOR ALL TRANSFER-RNA
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DOI：
10.1016/0014-5793(75)81093-3
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发表时间：
1975-01-01
期刊：
影响因子：
3.5
通讯作者：
STERNBACH, H
中科院分区：
文献类型：
--
作者：
CRAMER, F;FAULHAMMER, H;STERNBACH, H
在以前的工作中，我们发现面包酵母中的tRNAPhe被苯丙氨酰-tRNA合成酶[1，2]专一地在末端核糖的2‘羟基发生苯丙氨酰化。这是基于在tRNAPhe末端分别掺入3‘脱氧腺苷和2’脱氧腺苷后，tRNAPhe-CC-3‘da可以被氨酰化，而tRNAPhe-CC-2’da是该酶的竞争性抑制物。后来，通过一种独立的方法，从大肠杆菌和大鼠肝脏中获得了相同的结果[3]。从Zamecnik[4]提出的化学观点来看，这些结果似乎也是合理的，因为2‘羟基通常对酰化反应更活跃。然后，我们测试了酵母中的tRNAne、tRNASeT*、tRNatvr和TrNava‘，以检查更具活性的2’羟基的酶促氨酰化的一般有效性。然而，我们发现了三类tRNA：在2‘羟基发生氨酰化的，在3’羟基发生氨酰化的，以及在两个羟基都能发生氨酰化的。
In previous work we showed that tRNAPhe from baker’s yeast was phenylalanylated exclusively at the 2’hydroxyl group of the terminal ribose by phenylalanyl-tRNA synthetase [1, 2]. This was based on the observation that after incorporation of 3’deoxyadenosine and 2’deoxyadenosine, respectively, into the terminus of tRNAPhe only tRNAPhe-CC-3’dA could be aminoacylated whereas tRNAPhe-CC-2’dA was a competitive inhibitor of the enzyme. The same result was later obtained, by an independent method, for tRNAPhe from Escherichiu coli and from rat liver [3]. These results seemed to be reasonable also from the chemical point of view as suggested by Zamecnik [4] since the 2’hydroxyl group is generally more reactive towards acylation. We then tested tRNAne, tRNASeT*, tRNATvr, and tRNAVa’from yeast in order to check the general validity of the enzymatic aminoacylation of the more reactive 2’hydroxyl group. We found, however, three classes of tRNAs: those aminoacylated at the 2’hydroxyl group, those aminoacylated at the 3’hydroxyl group and those aminoacylatable at both hydroxyl groups.