Nonenzymatic, template-directed ligation of oligoribonucleotides is highly regioselective for the formation of 3'-5' phosphodiester bonds
Nonenzymatic, template-directed ligation of oligoribonucleotides is highly regioselective for the formation of 3'-5' phosphodiester bonds
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DOI：
10.1021/ja9537134
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发表时间：
1996-04-10
影响因子：
15
通讯作者：
Szostak, JW
中科院分区：
文献类型：
--
作者：
Rohatgi, R;Bartel, DP;Szostak, JW
We have found that nonenzymatic, template-directed ligation reactions of oligoribonucleotides display high selectivity for the formation of 3'-5' rather than 2'-5' phosphodiester bonds. Formation of the 3'-5'-linked product is favored regardless of the metal ion catalyst or the leaving group, and for several different ligation junction sequences. The degree of selectivity depends on the leaving group: the ratio of 3'-5' -to 2'-5'-linked products was 10-15:1 when the 5'-phosphate was activated as the imidazolide, and 60-80:1 when the 5'-phosphate was activated by formation of a 5'-triphosphate. Comparison of oligonucleotide ligation reactions with previously characterized single nucleotide primer extension reactions suggests that the strong preference for 3'-5'-linkages in oligonucleotide ligation is primarily due to the occurrence of ligation within the context of an extended Watson-Crick duplex. The ability of RNA to correctly self-assemble by template-directed ligation is an intrinsic consequence of its chemical structure and need not be imposed by an external catalyst (i.e., an enzyme polymerase); RNA therefore provides a reasonable structural basis for a self-replicating system in a prebiological world.
