VPB 112: General Veterinary Biochemistry (1+1)

TRANSFER RNA (t RNA)

•  They constitute about 15% of the total RNA in the cell. tRNA is also known as soluble RNA.
• t RNA is a small, single stranded molecule consists of approximately 75 – 90 nucleotides.
• It is the smallest of the 3 types of RNA.
• Structure of t RNA
  • All t RNA have a cloverleaf secondary structure, which is the arrangement that gives the maximum intramolecular complementary base pairing.
  • All t RNA molecule contains 4 main arms, viz.,
    • Amino acid acceptor arm consists of base sequences of CCA at the 3’ end, which carries the amino acid.
    • Anticodon arm, which includes the triplet anticodon that interacts with mRNA in the process of protein synthesis.
    • D arm, so called because of its high content of modified base dihydrouridine.
    • T Ψ C arm contains the T Ψ C sequence, where the Ψ is the modified base, pseudouridine.
  • There is at least one specific tRNA for each of the amino acid.
• Functions of t RNA
  • t RNA molecules activate amino acids and bring them to ribosome for protein synthesis.
  • t RNA is to recognize the codon of the mRNA to ensure that the correct amino acid is incorporated.