Unusual Bases in tRNA

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Ribose Nucleic Acids Comparison Between DNA and RNA Ribosomal RNA (rRNA) Characteristics of Different Ribosome Types Types of rRNA Synthesis of rRNA Messenger RNA (mRNA) Size of mRNA Structure of mRNA Stability of mRNA Synthesis of Messenger RNA - mRNA Polyadenylation Capping in mRNA Methylation in mRNA Heterogenous Nuclear RNA (hnRNA)

Unusual Bases in tRNA

Unusual Bases in tRNA - In addition to the usual bases A, U, G and C, tRNA contain a number of unusual bases, and in this respect differs from mRNA and rRNA. The unusual bases of tRNA account for 15-20% of the total RNA of the cell. Most of the unusual bases are formed by methylation (addition of -CHa or methyl group to the usual bases), e.g. cytosine and guanine on methylation yield methylcytosine and methyl/guanine, respectively.

Precursor tRNA molecules transcribed on the DNA template contains the usual bases. These are then modified to unusual bases. The unusual bases are important because they protect the tRNA molecule against degradation by RNase. This protection is necessary because RNA is found floating freely in the cell.

Some of the unusual bases of tRNA are methyl guanine (GMe), dimethylguanine(GMe2), methylcytosine (Me), ribothymine (T), pseudouridine (ψ), dihydrouridine (DHU, H2U, UH2), inosine (I) and methylinosine (IMe, MeI). In general, organisms high in the evolutionary scale contain more modified bases than lower organisms.

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Difference Between Prokaryotes and eukaryotes mRNA Transfer RNA (tRNA) OR Soluble RNA (sRNA) Structure of Transfer RNA - tRNA Unusual Bases in tRNA Classification of tRNA Invariant and Semi invariant Nucleotides Tertiary Structure of tRNA Initiator tRNA Specificity of tRNA Biosynthesis of tRNA Comparison of Different Types of RNA

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