Type I intron has the function of self splicing. In the splicing reaction, there should be a guanine nucleoside (containing free 3 '- OH) G-OH. G first binds to the 5 'end of the intron. When the linear intron becomes a ring, its 3' end can be 15 nucleotides away from the 5 'end, thus removing the original 5' end and 15 base (or more) segments (including G). This self splicing is based on the specific sequence of RNA Endonuclease Is catalyzed by the activity of. Type I introns are more common than type II introns. There is no relationship between the two types of introns. They have a common characteristic, that is, they can self splice in vitro without the catalysis of any protein enzyme. But in vivo they all need proteins to help them fold into secondary structures.
Type I introns exist in genes encoding rRNA, mRNA and tRNA in the nucleus, mitochondria and chloroplasts of some organisms.
