Splicing Mechanism (VIDEO) International School of Advanced Studies (SISSA) This video is under embargo. Please login to access this video. To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Caption The movie provides a direct view of the splicing mechanism catalyzed by the group II intron ribozymes. Magnified view of the ribozyme active site. The exon is shown in blue, the intron in green, Mg2+ ions are depicted as yellow spheres. The cleavage of the phosphodiester bond, connecting the intron and the exon of the ribozyme, occurs via a dissociative mechanism promoted by two Mg2+ ions: (i) the scissile phosphate breaks; (ii) the nucleophilic water attacks the scissile phosphate without being pre-activated by any specific base; (iii) the w Credit SISSA Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.