Purification, crystallization and preliminary structural characterization of the N-terminal region of the human formin-homology protein FHOD1

Formins are key regulators of actin cytoskeletal dynamics that constitute a diverse protein family that is present in all eukaryotes examined. They typically consist of more than 1000 amino acids and are defined by the presence of two conserved regions, namely the formin homology 1 and 2 domains. Additional conserved domains comprise a GTPase-binding domain for activation, a C-terminal autoregulation motif and an N-terminal recognition domain. In this study, the N-terminal region (residues 1-339) of the human formin homology domain-containing protein 1 (FHOD1) was purified and crystallized from 20%(w/v) PEG 4000, 10%(v/v) glycerol, 0.3 M magnesium chloride and 0.1 M Tris-HCl pH 8.0. Native crystals belong to space group P1, with unit-cell parameters a = 35.4, b = 73.9, c = 78.7 angstrom, alpha = 78.2, beta = 86.2, gamma = 89.7 degrees. They contain two monomers of FHOD1 in the asymmetric unit and diffract to a resolution of 2.3 angstrom using a synchrotron-radiation source.