Mechanism of N6-Threonylcarbamoyladenonsine (t<sup>6</sup>A) Biosynthesis: Isolation and Characterization of the Intermediate Threonylcarbamoyl-AMP
作者:Charles T. Lauhon
DOI:10.1021/bi301233d
日期:2012.11.6
bacteria for the biosynthesis of the universal tRNA modified base N6-threonylcarbamoyl adenosine (t6A). In this work, t6A biosynthesis in Bacillus subtilis has been reconstituted in vitro and found to indeed require the four proteins YwlC (TsaC), YdiB (TsaE), YdiC (TsaB) and YdiE (TsaD). YwlC was found to catalyze the conversion of l-threonine, bicarbonate/CO2 and ATP to give the intermediate l-threonylcarbamoyl-AMP
遗传和生化研究最近涉及细菌中通用tRNA修饰的碱基N6-苏氨酰氨基甲酰基腺苷(t 6 A)的生物合成所需的四种蛋白质。在这项工作中,枯草芽孢杆菌的t 6 A生物合成已在体外重建,发现确实需要四种蛋白质YwlC(TsaC),YdiB(TsaE),YdiC(TsaB)和YdiE(TsaD)。发现YwlC催化1-苏氨酸,碳酸氢盐/ CO 2和ATP的转化,得到中间体1-苏氨酰氨基甲酰基-AMP(TC-AMP)和焦磷酸盐作为产物。TC-AMP通过HPLC分离并通过质谱和11 H NMR。NMR分析表明,TC-AMP分解,得到AMP和几乎等摩尔的1-苏氨酸和5-甲基-2-恶唑烷酮-4-羧酸酯的终产物。在生理条件下(pH 7.5、37°C,2 mM MgCl 2),TC-AMP的半衰期为3.5分钟。YwlC(在存在焦磷酸酶的情况下)及其大肠杆菌同源物YrdC都催化TC-AMP的形成,而仅产生少量的AMP。这表明,CO