Crystal Structure of the PHF8 Jumonji Domain, an Nepsilon-methyl Lysine Demethylase

Crystallographic analysis of the catalytic domain of PHD finger protein 8 (PHF8), an N(epsilon)-methyl lysine histone demethylase associated with mental retardation and cleft lip/palate, reveals a double-stranded beta-helix fold with conserved Fe(II) and cosubstrate binding sites typical of the 2-oxoglutarate dependent oxygenases. The PHF8 active site is highly conserved with those of the FBXL10/11demethylases, which are also selective for the di-/mono-methylated lysine states, but differs from that of the JMJD2 demethylases which are selective for tri-/di-methylated states. The results rationalize the lack of activity for the clinically observed F279S PHF8 variant and they will help to identify inhibitors selective for specific N(epsilon)-methyl lysine demethylase subfamilies.