PHD fingers in ING2 and BPTF were recently shown to bind H3K4 -GST-PHD finger fusion on nitrocellulose array, washed w. peptide and did reverse. peptide array, wash w. GST fusion. -verified w. peptide pull down and western. used 150 mm NaCl and 300mM for stringent conditions. -7 of the yeast PHD fingers bound H3K4me3 peptide w. micromolar Kd. Therefore binding this mark is a common property of many PHD fingers. -all have a conserved W in their binding pocket. Mutating this abolishes binding in peptide pull down. -sequence shows they all have conserved Cys for Zn finger, Y, M, W for aeromatic cage and E,D for H3R2 interaction. -some don't have space for R2 and biochemical data shows these fingers don't interact w. h3K4. -mutating the W or the D abolished peptide binding.