Crystallization and preliminary X-ray crystallographic studies on apolipoprotein H (β2-glycoprotein-I) from human plasma

Apolipoprotein-H (Apo-H, Mw ≃ 50 kDa) is a carbohydrate-rich human-plasma protein which exists in blood serum in the free form as well as distributed between several classes of lipoproteins. Single crystals of apo-H have been obtained and crystallographic data sets have been collected. The crystals belong to the orthorhombic space group C2221, with cell dimensions a = 158.47, b = 169.25, c = 113.28 Å (at 100 K). The data indicate that the crystallographic asymmetric unit contains one tetramer of the protein.