Crystallization and Preliminary X-Ray Diffraction Studies of Oxidized Flavodoxin from Chondrus crispus, a Red Alga

Abstract

Crystals of the oxidized form of flavodoxin from a red alga, Chondrus crispus, have been grown in ammonium sulfate solution by the dialysis method. The crystals belong to the orthorhombic system, space group P2₁2₁2₁, with unit cell dimensions of a=63.6, b=48.8, and c=56.8 Å. The asymmetric unit contains one molecule of flavodoxin. The crystals diffract X-rays to about 2.0 Å resolution and are stable to X-ray beams. The diffraction patterns changed significantly upon soaking the crystal in a solution of a platinum complex. The major heavy-atom sites in the platinum derivative crystal have been identified from the difference Patterson function calculated at 4 Å resolution.