A model for histone H5-DNA interaction: simultaneous minor and major groove binding.

Using the tertiary structure of the globular domain of H5 (GH5) and based on an alternative sequence homology between GH5 and DNA-binding proteins containing the helix-turn-helix motif, a model for H5-DNA interaction is proposed. From molecular graphics it follows that helix II recognizes the major groove of the DNA, as does the second helix of the helix-turn-helix motif, while helix III makes minor groove contacts, in agreement with the hypothesis of Turnell et al. (FEBS letters 232, 263-268). In the resulting model GH5 makes contact with a full turn of DNA.