Crystallization and preliminary X-ray diffraction study of hemoglobin D from the Aldabra giant tortoise, Geochelone gigantea

Hemoglobin D (Hb D) from the Aldabra giant tortoise, Geochelone gigantea, was crystallized by the hanging drop vapor diffusion technique with a precipitant solution containing 10% polyethylene glycol 3350 and 50 mM HEPES-Na, pH 7.5. The Hb D crystals of G. gigantea, which diffract to at least a 2.0 A resolution, belong to the monoclinic space group C2 with unit cell dimensions of a = 112.1 A, b = 62.4 A, c = 54.0 A, and beta = 110.3 degrees. One alphabeta dimer molecule of Hb D existed in an asymmetric unit, with a calculated value of Vm of 2.77 A(3)Da(-1).