A
guanosine ribonucleotide (it has the
nitrogenous base guanine attached to the
sugar ribose) which has a
methyl group attached to the 7th ring
atom of the
guanine (a
nitrogen atom). These are found at the capped 5'-ends of
eukaryotic mRNA.
From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.