Purification, crystallization and preliminary X-ray diffraction studies of the β-catenin homolog HMP-2 from Caenorhabditis elegans.

β-Catenin is a multifunctional protein involved in both cell adhesion and Wnt signaling in metazoans. The nematode Caenorhabditis elegans is unusual in that it expresses four β-catenin paralogs with separate functions. C. elegans HMP-2 participates in cell adhesion but not in Wnt signaling, so structural and biochemical studies of this protein will help in understanding its unusual specialization and the evolution of β-catenin. HMP-2 was expressed, purified and crystallized in two different salt conditions. Crystals grown from a sodium formate condition diffracted to a resolution of 2 Å and belonged to space group C2, with unit-cell parameters a = 165.2, b = 39.0, c = 101.1 Å, β = 116.7°. Crystals obtained from a lithium sulfate condition diffracted to 3 Å resolution and belonged to space group P43, with unit-cell parameters a = b = 85.3, c = 138.7 Å. Diffraction data were collected and processed from both crystal forms and the structure was solved by molecular replacement. Model refinement is in progress.