Group I intron splicing requires
Group I introns are self-splicing ribozymes catalyzing their own excision via two transesterification steps that require external guanosine cofactor. Free guanosine or GMP, GDP, GTP binds specific G-binding pocket in P7 paired region of intron tertiary structure. Its 3' hydroxyl serves as nucleophile attacking 5' splice site, becoming covalently attached to intron 5' end, freeing upstream exon. Second attack by upstream exon 3' OH on 3' splice site ligates exons. No ATP hydrolyzed, reversible, aided in vivo by maturases. This refined regulation supports accurate ribosomal assembly, quality con
Ref: Watson Molecular Biology of the Gene, 7th ed., Chapter 15, Group I intron self-splicing requiring external guanosine
