Pseudo-uridylic acid

Different sites on the transfer-RNA molecule have been tentatively associated with the various possible biological functions (1) the CXTA terminus is the site for the attachment of the amino add it may be enzymatically renewed independently of transfer RNAs proper synthesis (2) other sites, common to all transfer RNAs, may be required for interactions at the level of ribosomes a tetranucleotide sequence T OC ( r for pseudo-uridylic acid) common to almost all transfer RNAs could play such a rdle (3) the anticodon (a trinucleotide segment) which engages with messenger RNA to insert the amino add in the correct sequence is easily... 

Detailed analysis of t-RNA molecules (similar results have been obtained with other classes of RNA and with DNA) has shown that although A, G, C, U (or T) are the major nucleotides a variety of other nucleotides are present. Some such as inosine (I) and pseudo-uridylic acid (IP) may be scattered within the molecules whereas others are limited to specific sites. Isopentenylaminopurine (IPA) appears to be located at a specific position near to the anticodon in certain t-RNAs (Fig. 5.15) and may play a part in the control of t-RNA activity through affecting the conformation of the anticodon loop or even the whole secondary structure of the molecule. Much remains to be learned about the potentially important functions of these uncommon nucleotides and considerable research effort is presently being directed to this end (see p. 298). 

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See also in sourсe #XX -- [ ]

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