Extended Data Fig. 9: Model of Group II RNP Life cycle.
From: Structural insights into intron catalysis and dynamics during splicing
In the first step of splicing, the 5′-exon (in black) is recognized and juxtaposed against the branchpoint A (shown as a star) of the D6 helix. The branching reaction occurs, forming the lariat bond (shown as a dash) and the D6 helix disengages from D1c and the thumb and DBD of the maturase protein, swinging downwards and bringing the 3′-exon into the active site. The 5′-splice site is now poised to attack the scissile phosphate of the 3′-exon, splicing the exons together. After the first two steps of splicing, the ligated exon is released and the apoRNP functions as a retroelement, undergoing retrotransposition, TPRT and transcription to complete the group II intron life cycle.
