Expression, purification, crystallization and preliminary X-ray characterization of the GRP carbohydrate-recognition domain from Homo sapiens.

Galectins are a family of animal lectins which share similar carbohydrate-recognition domains (CRDs) and an affinity for beta-galactosides. A novel human galectin-related protein named GRP (galectin-related protein; previously known as HSPC159) comprises only one conserved CRD with 38 additional N-terminal residues. The C-terminal fragment of human GRP (GRP-C; residues 38-172) containing the CRD has been expressed and purified. The protein was crystallized using the hanging-drop vapour-diffusion method from a solution containing 2% PEG 400 and 2M ammonium sulfate in 100 mM Tris-HCl buffer pH 7.5. Diffraction data were collected to a resolution limit of 2.0 angstroms at beamline 3W1A of Beijing Synchrotron Radiation Facility at 100 K. The crystals belong to the monoclinic space group C2, with unit-cell parameters a = 123.07, b = 96.67, c = 61.56 angstroms, beta = 118.72 degrees. The estimated Matthews coefficient was 2.6 angstroms3 Da(-1), corresponding to 51.8% solvent content.