Description of Ribozymes

The splicing reaction catalyzed by these introns consists of two steps  

The RNA interacts with the guanosine nucleotide whose 3 -OH is the attacking nucleophile for the first transesterification reaction (type a cleavage), and 

the IVS RNA interacts specifically with the stretch of pyrimidine residues at the end of the 5 exon that is the attacking group for the second transesterification reaction. 

Overall, the intron has a G added to its 5 -end and the intron is excised from the RNA precursor in the splicing reaction. 

2 Group II introns and spliceosome. Group II introns are primarily found 

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