Download AMINOACETYLATION OF t-RNA

Aminoacetylation of t-RNA
Aminoacyl-tRNA is tRNA (also known as transfer ribonucleic acid) to which its cognated amino acid is
adhered. Their role is to deliver the amino acid to the ribosome where it will be incorporated into the
polypeptide chain that is being produced. A specific amino acid is added to each tRNA, which is crucial
since it means that only that particular amino acid will be incorporated when the anticodon of that tRNA
fits the next codon of the mRNA that is being translated into protein.
The specific linkage of the correct amino acid to each tRNA is accomplished by aminoacyl-tRNA
synthetases. Due to the degeneracy of the genetic code, some of the different tRNAs have the same
amino acid attached to them. Aminoacyl-tRNA (also known as charged tRNA) is produced in two steps;
amino acid activation and transfer. The first step is the adenylation of the amino acid, which forms
aminoacyl-AMP:
Amino acid + ATP ↔ Aminoacyl-AMP + PPi
Then, the amino acid residue is transferred to the tRNA:
Aminoacyl-AMP + tRNA ↔ Aminoacyl-tRNA + AMP
The net reaction is
Amino acid + ATP + tRNA ↔ Aminoacyl-tRNA + AMP + PPi
Aminoacyl tRNA synthetase (aaRS) is an enzyme that catalyzes the esterification of a specific amino acid
or its precursor to one of all its compatible cognate tRNAs to form an aminoacyl-tRNA.
The synthetase first binds ATP and the corresponding amino acid or its precursor to form an aminoacyladenylate and release inorganic pyrophosphate (PPi). The adenylate-aaRS complex then binds the
appropriate tRNA molecule, and the amino acid is transferred from the aa-AMP to either the 2'- or 3'-OH
of the last tRNA base (A76) at the 3'-end. Some synthetases also mediate a proofreading reaction to
ensure high fidelity of tRNA charging; if the tRNA is found to be improperly charged, the aminoacyl-tRNA
bond is hydrolyzed.
Reaction:
Amino acid + ATP → aminoacyl-AMP + PPi
Aminoacyl-AMP + tRNA → aminoacyl-tRNA + AMP
Sum of 1 and 2: amino acid + tRNA + ATP → aminoacyl-tRNA + AMP + PPiAminoacetylation of t-RNA
Aminoacyl-tRNA is tRNA (also known as transfer ribonucleic acid) to which its cognated amino acid is
adhered. Their role is to deliver the amino acid to the ribosome where it will be incorporated into the
polypeptide chain that is being produced. A specific amino acid is added to each tRNA, which is crucial
since it means that only that particular amino acid will be incorporated when the anticodon of that tRNA
fits the next codon of the mRNA that is being translated into protein.
The specific linkage of the correct amino acid to each tRNA is accomplished by aminoacyl-tRNA
synthetases. Due to the degeneracy of the genetic code, some of the different tRNAs have the same
amino acid attached to them. Aminoacyl-tRNA (also known as charged tRNA) is produced in two steps;
amino acid activation and transfer. The first step is the adenylation of the amino acid, which forms
aminoacyl-AMP:
Amino acid + ATP ↔ Aminoacyl-AMP + PPi
Then, the amino acid residue is transferred to the tRNA:
Aminoacyl-AMP + tRNA ↔ Aminoacyl-tRNA + AMP
The net reaction is
Amino acid + ATP + tRNA ↔ Aminoacyl-tRNA + AMP + PPi
Aminoacyl tRNA synthetase (aaRS) is an enzyme that catalyzes the esterification of a specific amino acid
or its precursor to one of all its compatible cognate tRNAs to form an aminoacyl-tRNA.
The synthetase first binds ATP and the corresponding amino acid or its precursor to form an aminoacyladenylate and release inorganic pyrophosphate (PPi). The adenylate-aaRS complex then binds the
appropriate tRNA molecule, and the amino acid is transferred from the aa-AMP to either the 2'- or 3'-OH
of the last tRNA base (A76) at the 3'-end. Some synthetases also mediate a proofreading reaction to
ensure high fidelity of tRNA charging; if the tRNA is found to be improperly charged, the aminoacyl-tRNA
bond is hydrolyzed.
Reaction:
Amino acid + ATP → aminoacyl-AMP + PPi
Aminoacyl-AMP + tRNA → aminoacyl-tRNA + AMP
Sum of 1 and 2: amino acid + tRNA + ATP → aminoacyl-tRNA + AMP + PPi