Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, United States.
Biochemistry. 2012 Feb 21;51(7):1333-5. doi: 10.1021/bi201921a. Epub 2012 Feb 7.
The RNA ligase RtcB is conserved in all domains of life and is essential for tRNA maturation in archaea and metazoa. Here we show that bacterial and archaeal RtcB catalyze the GTP-dependent ligation of RNA with 3'-phosphate and 5'-hydroxyl termini. Reactions with analogues of RNA and GTP suggest a mechanism in which RtcB heals the 3'-phosphate terminus by forming a 2',3'-cyclic phosphate before joining it to the 5'-hydroxyl group of a second RNA strand. Thus, RtcB can ligate RNA cleaved by RNA endonucleases, which generate 2',3'-cyclic phosphate and then 3'-phosphate termini on one strand, and a 5'-hydroxyl terminus on another strand.
RNA 连接酶 RtcB 在所有生命领域都保守存在，并且对于古菌和后生动物的 tRNA 成熟是必需的。在这里，我们表明细菌和古菌的 RtcB 催化具有 3'-磷酸和 5'-羟基末端的 RNA 与 GTP 的依赖 GTP 的连接。与 RNA 和 GTP 类似物的反应表明，RtcB 通过在连接到第二条 RNA 链的 5'-羟基基团之前形成 2'，3'-环磷酸来修复 3'-磷酸末端的机制。因此，RtcB 可以连接由 RNA 内切核酸酶切割的 RNA，该酶在一条链上生成 2'，3'-环磷酸和 3'-磷酸末端，而在另一条链上生成 5'-羟基末端。
