Purification, crystallization and preliminary X-ray investigation of the complex of human vitamin D binding protein and rabbit muscle actin

The vitamin D binding protein binds globular actin with high affinity and i s involved in the clearance of actin from the blood circulation. A complex of the human vitamin D binding protein and rabbit muscle actin was subjecte d to purification steps. The pure complex was crystallized using the hangin g-drop vapour-diffusion procedure. The best obtained crystals belong to the monoclinic space group P2(1), with unit-cell parameters a = 74.44, b = 74. 90, c = 88.02 Angstrom, beta = 110.19 degrees. A complete data set to 2.4 A ngstrom was collected from a single crystal using synchrotron radiation at DESY, Hamburg, Germany.