Practice question

Five prime cap of eukaryotic messenger RNA contains modified nucleotide seven methylguanosine, formed after addition of guanosine not encoded by DNA. Guanine base is methylated at N7 position by cap methyltransferase RNMT using S-adenosylmethionine SAM as methyl donor, creating positively charged quaternary ammonium essential for specific recognition by eukaryotic initiation factor eIF4E during translation. Additional 2'-O methylations of first nucleotide creating cap one and second nucleotide creating cap two occur via CMTR1 and CMTR2 methyltransferases in higher eukaryotes enhancing innate immune evasion and translation efficiency.