The NMR structure of the PHD finger from human WSTF (Williams Syndrome Transcription Factor) shows that the conserved cysteines and histidine coordinate two Zn2+ ions.

In general, the PHD finger adopts a globular fold, consisting of a two-stranded beta-sheet and an alpha-helix.

The region consisting of these secondary structures and the residues involved in coordinating the zinc-ions are very conserved among species.

A protein called KDM5C has a PHD finger, which has been reported to bind histone H3 tri-methylated lysine 9 (H3K9me3).

[2] Based on these publications, binding to tri-methylated lysines on histones may therefore be a property widespread among PHD fingers.