Transfer RNA (tRNA): Difference between revisions
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In addition to the four stem loops, tRNA have a variable loop located in between the acceptor and D-stems. This variable loop can be quite small, but for some tRNA such as the serine or leucine-specific tRNA, it can form an additional helix. | In addition to the four stem loops, tRNA have a variable loop located in between the acceptor and D-stems. This variable loop can be quite small, but for some tRNA such as the serine or leucine-specific tRNA, it can form an additional helix. | ||
'''Modified nucleotides.''' Most tRNAs contain modified nucleotides<ref>PMID:20459084</ref>, which are added post-transcriptionally by specific enzymes. Common modifications include isomerisation of uridines into pseudouridines (Ψ), methylation of either the ribose and/or the base, thiolation, reduction of uridines into dihydrouridines (D). | '''Modified nucleotides.''' Most tRNAs contain modified nucleotides<ref>PMID:20459084</ref>, which are added post-transcriptionally by specific enzymes. Common modifications include isomerisation of uridines into [[Pseudourdine|pseudouridines]] (Ψ), methylation of either the ribose and/or the base, thiolation, reduction of uridines into dihydrouridines (D). | ||
[[Image:Pseudouridine.png|center|350px]] | [[Image:Pseudouridine.png|center|350px]] | ||
The anticodon loop of the tRNA quite often contains hypermodified bases, the function of which is to stabilize the codon-anticodon interaction within the ribosome. The nature and position of nucleotide modifications is both specific of the organism and the tRNA type. Common modified nucleotides include: | The anticodon loop of the tRNA quite often contains hypermodified bases, the function of which is to stabilize the codon-anticodon interaction within the ribosome. The nature and position of nucleotide modifications is both specific of the organism and the tRNA type. Common modified nucleotides include: | ||