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The CCA tail is a cytosine-cytosine-adenine sequence at the 3′ end of the tRNA molecule. The amino acid loaded onto the tRNA by aminoacyl tRNA synthetases, to form aminoacyl-tRNA, is covalently bonded to the 3′-hydroxyl group on the CCA tail. [9] This sequence is important for the recognition of tRNA by enzymes and critical in translation.
For example, if the amino acid that attach to the end is phenylalanine, the reaction will be catalyzed by phenylalanine-tRNA synthase to produce tRNA phe. [4] The other end—the bottom often called the "DNA arm"—consists of a three base sequence that pairs with a complementary base sequence in a mRNA. [5]
These so-called non-coding RNAs ("ncRNA") can be encoded by their own genes (RNA genes), but can also derive from mRNA introns. [32] The most prominent examples of non-coding RNAs are transfer RNA (tRNA) and ribosomal RNA (rRNA), both of which are involved in the process of translation. [7]
The amino acid is joined by its carboxyl group to the 3' OH of the tRNA by an ester bond. When the tRNA has an amino acid linked to it, the tRNA is termed "charged". In bacteria, this aminoacyl-tRNA is carried to the ribosome by EF-Tu, where mRNA codons are matched through complementary base pairing to specific tRNA anticodons. Aminoacyl-tRNA ...
In the mid-1960s, the role of tRNA in protein synthesis was being intensively studied. In 1965, Holley et al. purified and sequenced the first tRNA molecule, initially proposing that it adopted a cloverleaf structure, based largely on the ability of certain regions of the molecule to form stem loop structures. [60]
All together, the actual stability of the ester bond influences the susceptibility of the aa-tRNA to hydrolysis within the body at physiological pH and ion concentrations. It is thermodynamically favorable that the aminoacylation process yield a stable aa-tRNA molecule, thus providing for the acceleration and productivity of polypeptide synthesis.
They are composed of nucleotides, which are the monomer components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). If the sugar is ribose, the polymer is RNA; if the sugar is deoxyribose, a variant of ribose, the polymer is DNA.
The T-arm or T-loop is a specialized region on the tRNA molecule which acts as a special recognition site for the ribosome to form a tRNA-ribosome complex during protein biosynthesis or translation (biology). The T-arm has two components to it; the T-stem and the T-loop.