Chemistry:Queuosine

From HandWiki

Queuosine is a modified nucleoside that is present in certain tRNAs in bacteria and eukaryotes.[1][2] It contains the nucleobase queuine. Originally identified in E. coli, queuosine was found to occupy the first anticodon position of tRNAs for histidine, aspartic acid, asparagine and tyrosine.[3] The first anticodon position pairs with the third "wobble" position in codons, and queuosine improves accuracy of translation compared to guanosine.[4][5][6] Synthesis of queuosine begins with GTP. In bacteria, three structurally unrelated classes of riboswitch are known to regulate genes that are involved in the synthesis or transport of pre-queuosine1, a precursor to queuosine: PreQ1-I riboswitches, PreQ1-II riboswitches and PreQ1-III riboswitches.

Queuosine biosynthesis genes have also been found on phage genomes and may be involved in protection from genome degradation by the host.[7][8]

Metabolism

In August 2025, a significant breakthrough in queuosine metabolism was identified by an international team of researchers who solved a 30-year mystery regarding how the micronutrient is absorbed by human cells. The study identified the gene SLC35F2, previously known as an oncogene, as the specific high-affinity transporter responsible for salvaging queuosine and its precursor, queuine, from the gut microbiome and dietary sources. This discovery explains the mechanism by which this "hidden nutrient" is distributed across billions of human cells to facilitate the modification of transfer RNA (tRNA).[9]

The identification of the SLC35F2 transporter links queuosine availability directly to several critical physiological processes, including brain health, memory formation, and cancer suppression. Because humans cannot synthesize queuosine de novo, the efficiency of this transporter is essential for "fine-tuning" genetic translation by ensuring proper tRNA decoding. Researchers suggest that this discovery opens new avenues for therapeutic interventions, particularly in using queuosine as a biomarker or treatment target for metabolic regulation, stress response, and neurodevelopmental stability.[9]

References

  1. ↑ "Biosynthesis of the 7-deazaguanosine hypermodified nucleosides of transfer RNA". Bioorganic Chemistry 31 (1): 24–43. February 2003. doi:10.1016/S0045-2068(02)00513-8. PMID 12697167. 
  2. ↑ "Queuosine modification of tRNA: a case for convergent evolution". Molecular Genetics and Metabolism 74 (1–2): 147–159. 2001. doi:10.1006/mgme.2001.3216. PMID 11592812. 
  3. ↑ "Possible anticodon sequences of tRNA His, tRNA Asm, and tRNA Asp from Escherichia coli B. Universal presence of nucleoside Q in the first position of the anticondons of these transfer ribonucleic acids". Biochemistry 11 (2): 301–308. January 1972. doi:10.1021/bi00752a024. PMID 4550561. 
  4. ↑ "Wild-type tRNATyrG reads the TMV RNA stop codon, but Q base-modified tRNATyrQ does not". Nature 294 (5837): 188–190. November 1981. doi:10.1038/294188a0. PMID 29451243. Bibcode: 1981Natur.294..188B. 
  5. ↑ "Queuosine modification of the wobble base in tRNAHis influences 'in vivo' decoding properties". The EMBO Journal 4 (3): 823–827. March 1985. doi:10.1002/j.1460-2075.1985.tb03704.x. PMID 2988936. 
  6. ↑ "Improvement of reading frame maintenance is a common function for several tRNA modifications". The EMBO Journal 20 (17): 4863–4873. September 2001. doi:10.1093/emboj/20.17.4863. PMID 11532950. 
  7. ↑ "Comparative Genomics of Bacteriophage of the Genus Seuratvirus". Genome Biology and Evolution 10 (1): 72–76. January 2018. doi:10.1063/5.0085058.7. PMID 29272407. 
  8. ↑ "Genome annotation and intraviral interactome for the Streptococcus pneumoniae virulent phage Dp-1". Journal of Bacteriology 193 (2): 551–562. January 2011. doi:10.1128/JB.01117-10. PMID 21097633. 
  9. ↑ 9.0 9.1 Burtnyak, L. et al. (August 21, 2025). "The oncogene SLC35F2 is a high-specificity transporter for the micronutrients queuine and queuosine". Proceedings of the National Academy of Sciences 122 (25). doi:10.1073/pnas.2425364122. PMC 12207525. https://www.pnas.org/doi/10.1073/pnas.2425364122. Retrieved April 10, 2026. 

Further reading



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