The MethylCap protein has been extensively validated for specific isolation of DNA fragments containing methylated CpGs. It consists of the methyl-CpG-binding domain (MBD) of human MeCP2, as a C-terminal fusion with Glutathione-S-transferase (GST) containing an N-terminal His6-tag. A single fully methylated CpG is sufficient for the interaction between the MethylCap protein and methylated DNA fragments.