Crystallization of the Fab fragment of the tumour-specific antibody PR1A3

PR1A3 antibody binds specifically to the tumour-associated cell-surface antigen, carcinoembryonic antigen. Crystals of the Fab fragment of the PR1A3 antibody were obtained by vapour diffusion against mother liquor containing Tris–HC1 buffer, pH 8.6, magnesium chloride and polyethylene glycol 4000 as precipitating agent. Crystals belong to the monoclinic space group P2₁ with cell dimensions a = 42.2, b = 216.7, c = 45.9 Å and β = 95.6°. Two Fab fragments are proesent in the asymmetric unit. Diffracted intensities up to 2.9 Å resolution have been measured from frozen crystals.