来自大肠杆菌的硫缺乏转运RNA对异亮氨酸的接受增加。
Increased isoleucine acceptance by sulfur-deficient transfer RNA from Escherichia coli.
作者信息
Harris C L, Marashi F, Titchener E B
出版信息
Nucleic Acids Res. 1976 Aug;3(8):2129-42. doi: 10.1093/nar/3.8.2129.
Sulfur-deficient tRNA, isolated from Escherichia coli HfrC, rel-, met-, cys-, lambda, after cysteine starvation, was found to have an increased acceptance of isoleucine in proportion to the deficiency of 4-thiouridine. Isoleucine acceptance was not altered in the presence of other amino acids of CTP, and the higher acceptance was observed over a wide range of magnesium, isoleucine, tRNA and enzyme concentrations. The Vmax value for sulfur-deficient tRNA was more than three times greater than observed for normal tRNA. Methylated albumin kieselguhr (MAK) chromatography revealed three isoacceptor peak for normal tRNA, while sulfur-deficient tRNA was missing tRNAile, and exhibited a larger, shifted peaks for tRNA normal tRNA, while sulfur-deficient tRNA was missing tRNAille 2, and exhibited a large shifted peak for tRNAile 3 . Treatment with crude RNA sulfurtransferase both lowered the isoleucine acceptance for sulfur-deficient tRNA to that seen for normal tRNA, and restored the missing isoacceptor on MAK. The possibility that thionucleotides may play a role in the aminoacylation of tRNAile in E. coli is discussed.
从半胱氨酸饥饿后的大肠杆菌HfrC、rel -、met -、cys -、λ中分离出的缺硫tRNA，发现其异亮氨酸接纳量随4 -硫尿苷的缺乏而增加。在存在其他氨基酸或CTP的情况下，异亮氨酸接纳量未改变，并且在广泛的镁、异亮氨酸、tRNA和酶浓度范围内都观察到了较高的接纳量。缺硫tRNA的Vmax值比正常tRNA观察到的值大三倍多。甲基化白蛋白硅藻土（MAK）色谱显示正常tRNA有三个同功受体峰，而缺硫tRNA缺少tRNAile 2，并且tRNAile 3出现一个较大的移位峰。用粗RNA硫转移酶处理既降低了缺硫tRNA对异亮氨酸的接纳量，使其降至正常tRNA的水平，又恢复了MAK上缺失的同功受体。讨论了硫代核苷酸可能在大肠杆菌tRNAile的氨酰化中起作用的可能性。
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