EMD-33811
Cryo-EM structure of Tetrahymena ribozyme conformation 5 undergoing the second-step self-splicing
EMD-33811
Single-particle2.97 Å
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Map released: 29/03/2023
Last modified: 03/07/2024
Sample Organism:
Tetrahymena
Sample: Cryo-EM structure of Tetrahymena ribozyme conformation 5 undergoing the second-step self-splicing
Fitted models: 7yg8 (Avg. Q-score: 0.419)
Deposition Authors: Li S, Michael ZP, Zhang X, Greg P, Zhang K
,
Zhang K
,
Liu L
Sample: Cryo-EM structure of Tetrahymena ribozyme conformation 5 undergoing the second-step self-splicing
Fitted models: 7yg8 (Avg. Q-score: 0.419)
Deposition Authors: Li S, Michael ZP, Zhang X, Greg P, Zhang K
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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 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.
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.