Snapshots of the second-step self-splicing of Tetrahymena ribozyme revealed by cryo-EM.

ABSTRACT: Group I introns are catalytic RNAs that coordinate two consecutive transesterification reactions for self-splicing. To understand how the group I intron promotes catalysis and coordinates self-splicing reactions, we determine the structures of L-16 Tetrahymena ribozyme in complex with a 5'-splice site analog product and a 3'-splice site analog substrate using cryo-EM. We solve six conformations from a single specimen, corresponding to different splicing intermediates after the first ester-transfer reaction. The structures reveal dynamics during self-splicing, including large conformational changes of the internal guide sequence and the J5/4 junction as well as subtle rearrangements of active-site metals and the hydrogen bond formed between the 2'-OH group of A261 and the N2 group of guanos

SUBMITTER: Li S 

PROVIDER: S-EPMC10020454 | biostudies-literature | 2023 Mar

REPOSITORIES: biostudies-literature