TRNA
Transfer RNA molecules (tRNA's) are small RNA molecules usually approximately 80 nucleotides in length, that function as adaptor molecules during the translation of mRNA into an amino acid sequence[1].
Structure
The structure of tRNA arises through the ability of RNA to fold into three-dimensional shapes using Watson and Crick base pairing. If there are large enough regions of overlap tRNA will fold into a shape that resembles a cloverleaf. This will undergo further folding, by hydrogen bonding, to form a compact L-shaped structure.[1]
The cloverleaf structure of tRNA is composed of an anticodon, a triplet of nucleotides that is complementary to corresponding codons on mRNA nolecules. tRNAS also have a short single stranded region at a tRNAs 3' end where amino acids that match an mRNA codon are attached[2].
Function
The amino acids that bond to produce a protein do not bind to mRNA. They require an adaptor molecule to bind to mRNA at one point and to the amino acid at another. This adaptor molecule is tRNA.
The genetic code is described as redundant/degenerate as there are 64 codons coding for only 20 amino acids. There is more than one tRNA molecule for some of the amino acids. Some tRNAs can bind to more than one codon. The theory of one tRNA being able to bind to more than one codon is known as the Wobble hypothesis[3].
- ↑ 1.0 1.1 Snustad, D. Peter. (2010). Principles Of Genetics.Hobeken: Wiley & Sons Cite error: Invalid
<ref>tag; name "null" defined multiple times with different content - ↑ Champe et al.(2008). Biochemistry. Baltimore: Lippincott Williams &amp;amp;amp;amp;amp;amp;amp;amp; Wilkins
- ↑ Alberts, Bruce et al. (2008). Molecular Biology of the Cell. New York: Garland Science