7ygc

Publication Abstract from PubMed

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 guanosine substrate. These results help complete a detailed structural and mechanistic view of this paradigmatic group I intron undergoing the second step of self-splicing.

Snapshots of the second-step self-splicing of Tetrahymena ribozyme revealed by cryo-EM.,Li S, Palo MZ, Zhang X, Pintilie G, Zhang K Nat Commun. 2023 Mar 16;14(1):1294. doi: 10.1038/s41467-023-36724-5. PMID:36928031^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.