Crystallization and preliminary crystallographic analysis of a partial extracellular fragment of a sperm membrane protein YWK-II/APPH related to the Alzheimer βA4-amyloid precursor protein

Crystals of a partial extracellular fragment of a human sperm membrane protein YWK-II/APPH have been grown at 291 K using PEG 4000 as precipitant. The diffraction pattern of the crystal extends to 2.8 Å resolution at 100 K using Cu Kα radiation. The crystals belong to space group P2₁2₁2₁, with unit-cell parameters a = 46.009, b = 67.387, c = 149.241 Å, α = β = γ = 90°. The presence of two molecules per asymmetric unit gives a crystal volume per protein mass (V_M) of 3.51 ų Da⁻¹ and a solvent content of 64.6% by volume. A full set of X-ray diffraction data were collected to 2.8 Å resolution from the native crystal.