Structure Of Transfer RNA

Structure of transfer RNA (tRNA):tRNA molecule contains 71-80 nucleotides with a molecular weight of about 25000. There are at least 20 species of 20 amino acids present in protein structure.

The structure of RNA depicted resembles that of a clover leaf. tRNA contains mainly four arms, each arm contains a base paired stem.

• The Acceptor Arm : This arm is capped with a sequence CCA. The amino acid is attached to the acceptor arm.
• The anticodon arm : this arm with the three specific nucleotide base is responsible for the recognition of triple codon of mRNA. The codon and anticadon are complementary to each other.
• The D arm : it is so named due to the presence of dihydrouridine.
• The T¥C arm : this arm contains a sequence of T pseudouridine and C.
• The variable arm: This arm is the most variable in tRNA.Based on this variability tRNA are two catagaries.

A)  Class I tRNA: the most predominant form with 3-5 base pairs lenth.

B)   Class II tRNA: they contain 13-20 base pair long arm