Structural insights into the decoding capability of isoleucine tRNAs with lysidine and agmatidine
The anticodon modifications of transfer RNAs (tRNAs) finetune the codon recognition on the ribosome for accurate translation. Bacteria and archaea utilize the modified cytidines, lysidine (L) and agmatidine (agm 2 C), respectively, in the anticodon of tRNA Ile to decipher AUA codon. L and agm 2 C co...
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Published in | Nature structural & molecular biology Vol. 31; no. 5; pp. 817 - 825 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
New York
Nature Publishing Group US
01.05.2024
Nature Publishing Group |
Subjects | |
Online Access | Get full text |
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Summary: | The anticodon modifications of transfer RNAs (tRNAs) finetune the codon recognition on the ribosome for accurate translation. Bacteria and archaea utilize the modified cytidines, lysidine (L) and agmatidine (agm
2
C), respectively, in the anticodon of tRNA
Ile
to decipher AUA codon. L and agm
2
C contain long side chains with polar termini, but their functions remain elusive. Here we report the cryogenic electron microscopy structures of tRNAs
Ile
recognizing the AUA codon on the ribosome. Both modifications interact with the third adenine of the codon via a unique C–A geometry. The side chains extend toward 3′ direction of the mRNA, and the polar termini form hydrogen bonds with 2′-OH of the residue 3′-adjacent to the AUA codon. Biochemical analyses demonstrated that AUA decoding is facilitated by the additional interaction between the polar termini of the modified cytidines and 2′-OH of the fourth mRNA residue. We also visualized cyclic
N
6
-threonylcarbamoyladenosine (ct
6
A), another tRNA modification, and revealed a molecular basis how ct
6
A contributes to efficient decoding.
Precise protein synthesis is achieved by tRNA modifications. Here the authors revealed that modified cytidines in tRNA
Ile
use their long side chains to make additional interactions with mRNA for stable tRNA binding on the ribosome. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1545-9993 1545-9985 |
DOI: | 10.1038/s41594-024-01238-1 |