Mueller E G, Buck C J, Palenchar P M, Barnhart L E, Paulson J L
Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA.
Nucleic Acids Res. 1998 Jun 1;26(11):2606-10. doi: 10.1093/nar/26.11.2606.
All organisms modify the bases of their RNA after transcription. Relatively little is known about the functions that these chemical alterations serve and, with very few exceptions, even less has been established regarding the enzymology involved. One modified base of known function is 4-thiouridine at position 8 of certain bacterial tRNAs, which serves as a photosensor for near-UV light. A gene involved in the conversion of uridine at position 8 into 4-thiouridine has been identified by genetic screening and its role in 4-thiouridine generation has been confirmed biochemically. This same gene, thiI , has recently been shown to play a role in thiamin biosynthesis. The purification and characteristics of the purified protein are also reported.
所有生物体在转录后都会对其RNA的碱基进行修饰。对于这些化学修饰所起的作用,我们了解得相对较少,而且除了极少数例外情况,关于其中涉及的酶学知识更是知之甚少。一种已知功能的修饰碱基是某些细菌tRNA第8位的4-硫尿苷,它作为近紫外光的光传感器。通过遗传筛选鉴定出了一个参与将第8位尿苷转化为4-硫尿苷的基因,并通过生化方法证实了其在4-硫尿苷生成中的作用。同一个基因thiI最近被证明在硫胺素生物合成中发挥作用。本文还报道了该纯化蛋白的纯化过程及其特性。