Katze J R, Gündüz U, Smith D L, Cheng C S, McCloskey J A
Biochemistry. 1984 Mar 13;23(6):1171-6. doi: 10.1021/bi00301a022.
Queuine (the base of queuosine, Q) catalytically reduced with tritium or deuterium yields a derivative in which the proton at C-8 (purine numbering system) has been exchanged and the cyclopentene ring has been reduced to a cyclopentane ring. Mouse fibroblast tRNA has been labeled by culturing the cells in medium supplemented with [3H]- and [2H]dihydroqueuine. Such tRNA yields, upon hydrolysis, the nucleoside dihydroqueuosine and a saccharide derivative of dihydroqueuosine. Each product has been identified unambiguously by mass spectrometry and chromatography. Both the 3H- and 2H-labeled material coeluted, and no unlabeled Q nucleoside was found. Therefore, dihydroqueuine is incorporated intact into tRNA in mammalian cells. Furthermore, fractionation of the labeled tRNA on concanavalin A-agarose, which specifically binds the mannosyl-Q-containing tRNAAsp, has shown that the dihydroqueuosine-containing tRNAAsp is mannosylated. This is the first direct evidence that queuine is incorporated intact into mammalian tRNA in vivo.
用氚或氘催化还原的异戊烯基腺苷（queuosine的碱基，Q）会产生一种衍生物，其中C-8（嘌呤编号系统）上的质子已被交换，且环戊烯环已还原为环戊烷环。通过在补充有[3H]-和[2H]二氢异戊烯基腺苷的培养基中培养细胞，小鼠成纤维细胞tRNA已被标记。这种tRNA水解后会产生核苷二氢异戊烯基腺苷和二氢异戊烯基腺苷的糖类衍生物。每种产物都已通过质谱和色谱法明确鉴定。3H-和2H-标记的物质共洗脱，未发现未标记的Q核苷。因此，二氢异戊烯基腺苷完整地掺入哺乳动物细胞的tRNA中。此外，在伴刀豆球蛋白A-琼脂糖上对标记的tRNA进行分级分离，该琼脂糖特异性结合含甘露糖基-Q的天冬氨酸tRNA（tRNAAsp），结果表明含二氢异戊烯基腺苷的tRNAAsp被甘露糖基化。这是异戊烯基腺苷在体内完整掺入哺乳动物tRNA的首个直接证据。
