Crystallization and preliminary X-ray diffraction analysis of the BRPF1 bromodomain in complex with its H2AK5ac and H4K12ac histone-peptide ligands.

The bromodomain-PHD finger protein 1 (BRPF1) is an essential subunit of the monocytic leukemia zinc (MOZ) histone acetyltransferase (HAT) complex and is required for complex formation and enzymatic activation. BRPF1 contains a structurally conserved bromodomain, which recognizes specific acetyllysine residues on histone proteins. The MOZ HAT plays a direct role in hematopoiesis, and deregulation of its activity is linked to the development of acute myeloid leukemia. However, the molecular mechanism of histone-ligand recognition by the BRPF1 bromodomain is currently unknown. The 117-amino-acid BRPF1 bromodomain was overexpressed in Escherichia coli and purified to homogeneity. Crystallization experiments of the BRPF1 bromodomain in complex with its H4K12ac and H2AK5ac histone ligands yielded crystals that were suitable for high-resolution X-ray diffraction analysis. The BRPF1 bromodomain-H4K12ac crystals belonged to the tetragonal space group P43212, with unit-cell parameters a = 75.1, b = 75.1, c = 86.3 Å, and diffracted to a resolution of 1.94 Å. The BRPF1 bromodomain-H2AK5ac crystals grew in the monoclinic space group P21, with unit-cell parameters a = 60.9, b = 55.6, c = 82.1 Å, β = 93.6°, and diffracted to a resolution of 1.80 Å. Complete data sets were collected from both crystal forms using synchrotron radiation on beamline X29 at Brookhaven National Laboratory (BNL).