Transfer RNA: Difference between revisions

Revision as of 23:56, 9 February 2025

Type of RNA molecule that helps decode a messenger RNA (mRNA) sequence into a protein

Transfer RNA (tRNA) is a type of RNA molecule that helps decode a messenger RNA (mRNA) sequence into a protein. tRNAs function at specific sites in the ribosome during translation, which is a process that synthesizes a protein from an mRNA molecule.

Structure

Transfer RNA molecules are typically 76 to 90 nucleotides in length and have a characteristic cloverleaf structure. This structure includes four arms: the acceptor stem, the T_C arm, the anticodon arm, and the D arm. The acceptor stem is where the amino acid is attached, while the anticodon arm contains the anticodon, a sequence of three nucleotides that is complementary to the mRNA codon.

Function

During protein synthesis, tRNA molecules transport specific amino acids to the ribosome, where they are added to the growing polypeptide chain. Each tRNA is specific to one amino acid and has an anticodon that pairs with the corresponding codon on the mRNA.

Aminoacylation

The process of attaching an amino acid to its corresponding tRNA is called aminoacylation. This reaction is catalyzed by enzymes known as aminoacyl tRNA synthetases. Each aminoacyl tRNA synthetase is specific for one amino acid and its corresponding tRNAs.

Role in Translation

Animation of tRNA function in translation

In the ribosome, tRNA molecules align with mRNA codons through base pairing between the anticodon and the codon. This ensures that the correct amino acid is added to the polypeptide chain. The ribosome facilitates the formation of peptide bonds between adjacent amino acids, thus elongating the protein.

tRNA Genes

The genes encoding tRNA molecules are transcribed by RNA polymerase III in eukaryotes. These genes are often found in clusters in the genome and are transcribed as precursor molecules that are processed to form mature tRNAs.

Evolution

The structure and function of tRNA are highly conserved across all domains of life, indicating their ancient origin. The evolution of tRNA is closely linked to the evolution of the genetic code and the translation machinery.

Related pages

References

Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2002). Molecular Biology of the Cell. 4th edition. New York: Garland Science.
Lodish, H., Berk, A., Zipursky, S. L., Matsudaira, P., Baltimore, D., & Darnell, J. (2000). Molecular Cell Biology. 4th edition. New York: W. H. Freeman.

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-'''Transfer RNA''' (tRNA) is a type of [[RNA]] that plays an integral role in [[protein synthesis]] within cells. It is responsible for decoding the [[mRNA]] sequence into a protein.
+{{short description|Type of RNA molecule that helps decode a messenger RNA (mRNA) sequence into a protein}}
+{{Use dmy dates|date=October 2023}}
-== Structure ==
+'''Transfer RNA''' ('''tRNA''') is a type of [[RNA]] molecule that helps decode a [[messenger RNA]] (mRNA) sequence into a [[protein]]. tRNAs function at specific sites in the [[ribosome]] during [[translation (biology)|translation]], which is a process that synthesizes a protein from an mRNA molecule.
-tRNA is a single-stranded RNA molecule that folds into a three-dimensional structure. This structure is often represented as a cloverleaf shape, with the [[anticodon]] loop and the [[amino acid]] attachment site at opposite ends.
-== Function ==
+==Structure==
-The primary function of tRNA is to transport amino acids to the [[ribosome]] during protein synthesis. Each tRNA molecule is specific for one amino acid and one or several codons. The anticodon of the tRNA pairs with the codon of the mRNA in the ribosome, ensuring that the correct amino acid is incorporated into the growing polypeptide chain.
+[[File:TRNA-Phe yeast en.svg|thumb|Diagram of tRNA structure]]
+Transfer RNA molecules are typically 76 to 90 nucleotides in length and have a characteristic cloverleaf structure. This structure includes four arms: the acceptor stem, the T_C arm, the anticodon arm, and the D arm. The acceptor stem is where the amino acid is attached, while the anticodon arm contains the anticodon, a sequence of three nucleotides that is complementary to the mRNA codon.
-== Synthesis ==
+==Function==
-tRNA molecules are synthesized by [[RNA polymerase III]] in the nucleus. The initial transcript, known as pre-tRNA, undergoes several modifications before it is functional. These modifications include the addition of the CCA sequence at the 3' end, which is the site of amino acid attachment, and the removal of introns.
+[[File:Peptide syn.svg|thumb|The role of tRNA in protein synthesis]]
+During protein synthesis, tRNA molecules transport specific amino acids to the ribosome, where they are added to the growing polypeptide chain. Each tRNA is specific to one amino acid and has an anticodon that pairs with the corresponding codon on the mRNA.
-== Types ==
+==Aminoacylation==
-There are different types of tRNA for each of the 20 amino acids. In addition, there are several tRNA molecules for each amino acid, each recognizing a different codon. This redundancy is known as the [[wobble hypothesis]].
+The process of attaching an amino acid to its corresponding tRNA is called aminoacylation. This reaction is catalyzed by enzymes known as [[aminoacyl tRNA synthetases]]. Each aminoacyl tRNA synthetase is specific for one amino acid and its corresponding tRNAs.
-== Role in disease ==
+==Role in Translation==
-Mutations in tRNA genes can lead to disease. For example, mutations in the gene for mitochondrial tRNA for leucine have been associated with [[Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes|MELAS syndrome]].
+[[File:Trna.gif|thumb|Animation of tRNA function in translation]]
+In the ribosome, tRNA molecules align with mRNA codons through base pairing between the anticodon and the codon. This ensures that the correct amino acid is added to the polypeptide chain. The ribosome facilitates the formation of peptide bonds between adjacent amino acids, thus elongating the protein.
-== See also ==
+==tRNA Genes==
-* [[Aminoacyl tRNA synthetase]]
+[[File:TRNA-Phe yeast 1ehz.png|thumb|3D structure of tRNA]]
-* [[Codon]]
+The genes encoding tRNA molecules are transcribed by [[RNA polymerase III]] in [[eukaryotes]]. These genes are often found in clusters in the genome and are transcribed as precursor molecules that are processed to form mature tRNAs.
-* [[Translation (biology)]]
+==Evolution==
+The structure and function of tRNA are highly conserved across all domains of life, indicating their ancient origin. The evolution of tRNA is closely linked to the evolution of the genetic code and the translation machinery.
+==Related pages==
+* [[Ribosomal RNA]]
+* [[Messenger RNA]]
+* [[Protein biosynthesis]]
+==References==
+* Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2002). ''Molecular Biology of the Cell''. 4th edition. New York: Garland Science.
+* Lodish, H., Berk, A., Zipursky, S. L., Matsudaira, P., Baltimore, D., & Darnell, J. (2000). ''Molecular Cell Biology''. 4th edition. New York: W. H. Freeman.
 [[Category:RNA]]
-[[Category:Protein synthesis]]
+[[Category:Protein biosynthesis]]
-[[Category:Molecular biology]]
-{{stub}}