Abstract
In bacterial tRNAs, 5-carboxymethoxyuridine (cmo5U) and its derivatives at the first position of the anticodon facilitate non-Watson–Crick base pairing with guanosine and pyrimidines at the third positions of codons, thereby expanding decoding capabilities. However, their biogenesis and physiological roles remained to be investigated. Using reverse genetics and comparative genomics, we identify two factors responsible for 5-hydroxyuridine (ho5U) formation, which is the first step of the cmo5U synthesis: TrhP (formerly known as YegQ), a peptidase U32 family protein, is involved in prephenate-dependent ho5U formation; and TrhO (formerly known as YceA), a rhodanese family protein, catalyzes oxygen-dependent ho5U formation and bypasses cmo5U biogenesis in a subset of tRNAs under aerobic conditions. E. coli strains lacking both trhP and trhO exhibit a temperature-sensitive phenotype, and decode codons ending in G (GCG and UCG) less efficiently than the wild-type strain. These findings confirm that tRNA hydroxylation ensures efficient decoding during protein synthesis.
Highlights
In bacterial tRNAs, 5-carboxymethoxyuridine and its derivatives at the first position of the anticodon facilitate non-Watson–Crick base pairing with guanosine and pyrimidines at the third positions of codons, thereby expanding decoding capabilities
We revealed that cmo5U34 is present as a major wobble modification in tRNALeu[3] and tRNAVal[1], whereas mcmo5U34 is primarily present in tRNAAla[1], tRNASer[1], tRNAPro[3], and tRNAThr[4] in E. coli[13] (Fig. 1b)
To search for genes responsible for RNA modifications, we developed a method called ribonucleome analysis to screen knockout strains for uncharacterized genes by liquid chromatography–mass spectrometry (LC/MS)[31]
Summary
In bacterial tRNAs, 5-carboxymethoxyuridine (cmo5U) and its derivatives at the first position of the anticodon facilitate non-Watson–Crick base pairing with guanosine and pyrimidines at the third positions of codons, thereby expanding decoding capabilities. Their biogenesis and physiological roles remained to be investigated. TRNA serves as an adapter molecule to connect codons on mRNA with the corresponding amino acids After they are transcribed, tRNAs undergo chemical modifications mediated by site-specific tRNA-modifying enzymes. Xm5(s2)U34 plays a critical role in stabilizing U-G wobble pairing at the A-site of the ribosome[10,11]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
