Pseudouridiini

Pseudouridiini is an isomer of the nucleoside uridine. In uridine, the glycosidic bond connects the base uracil to the ribose sugar at the N1 position of uracil. In pseudouridine, this bond is formed between the C1 position of uracil and the C1' position of the ribose sugar, hence the "pseudo" designation. This seemingly small structural difference has significant implications for its biological roles.

Pseudouridine is the most abundant modified nucleoside found in all types of RNA, including messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). Its presence can influence RNA structure, stability, and function. In tRNA, pseudouridine is often found in the anticodon loop and is crucial for proper codon recognition and translation fidelity. In rRNA, it contributes to the overall three-dimensional structure of ribosomes, which is essential for protein synthesis.

The pseudouridylation of RNA is catalyzed by a family of enzymes called pseudouridine synthases. These enzymes can modify specific uracil residues within RNA molecules. The biological significance of pseudouridine is underscored by its association with various cellular processes and diseases. For instance, alterations in pseudouridine levels or the activity of pseudouridine synthases have been implicated in cancer and other disorders. Research into pseudouridine continues to shed light on fundamental aspects of RNA biology and its role in health and disease.