Mechanism of action of a yeast RNA ligase in tRNA splicing - ScienceDirect

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作者：

Chris，L.，Greer，and，Craig，L.，Peebles，and，Peter，Gegenheimer

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摘要：

The yeast endonuclease and ligase activities that carry out the splicing of tRNA precursors in vitro have been physically separated. The properties of a partially purified ligase fraction were examined. The ligase requires a divalent cation and a nucleoside triphosphate as cofactor. The product of ligation is a 2′-phosphomonoester, 3′,5′-phosphodiester linkage. The phosphate in the newly formed phosphodiester bond comes from the γ position of ATP, while the 2′ phosphate is derived from the RNA substrate. An adenylylated enzyme intermediate was identified by incorporation of label from α-32P-ATP. Adenylylation was reversed by pyrophosphate, releasing ATP, whereas ligation was accompanied by release of AMP. Polynucleotide kinase and cyclic phosphodiesterase activities copurify with the adenylylated protein and may be required for the tRNA splicing reaction.

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关键词：

Magnesium Polynucleotide 5'-Hydroxyl-Kinase Phosphoric Diester Hydrolases 2',3'-Cyclic-Nucleotide Phosphodiesterases Polynucleotide Ligases RNA Ligase (ATP Adenosine Monophosphate Adenosine Triphosphate Chemistry RNA Splicing