Expression, crystallization and X-ray data collection from microcrystals of the extracellular domain of the human inhibitory receptor expressed on myeloid cells IREM-1

IREM-1 is an inhibitory receptor involved in the functional regulation of myeloid cells. The expression, in vitro folding, purification, crystallization and X-­ray data collection of the Ig-V like domain of IREM-1 are reported. X-ray data were collected from a microcrystal (300 × 10 × 10 µm) at 100 K and a diffraction pattern was obtained to 2.6 Å resolution on microfocus beamline ID23-2 at the ESRF. The crystal belongs to space group P3₁21, with unit-cell parameters a = b = 54.23, c = 72.02 Å, α = γ = 90, β = 120°. Assuming the presence of one molecule per asymmetric unit, V_M (the Matthews coefficient) was calculated to be 1.96 ų Da⁻¹ and the solvent content was estimated to be 37.27%. Determination of the IREM-1 structure will provide insights into its structural requirements for ligand discrimination and binding.