In the case of yeast tRNA (phenyl alanine) there is a G-U base pair (G4-U69), and many bases are methylatedlated like G26(2'methylated), C49(5'methylated), C40(5'methylated), and so on. If we look at the tertiary structure (L-shape of tRNA), we come across many unusual bases (I mean a deviation from normal WC bases) but still there is a maximization of Watson-Crick base-pair and stacking interaction so tRNA is stable and functional. What are the consequences of these methylated bases and what may be the impact of the unusual bases?