Crystallization of the complex of a monoclonal Fab fragment with the histidine-containing protein of the phosphoenolpyruvate: sugar phosphotransferase system of Escherichia coli.

Single crystals of the complex of a monoclonal Fab fragment with the histidine-containing protein of the phosphoenolpyruvate:sugar phosphotransferase system of Escherichia coli have been grown. This represents one of the first Fab-protein antigen complexes in which the same Fab fragment has previously been crystallized in the uncomplexed state and the structure solved (Prasad, L., Vandonselaar, M., Lee, J. S., and Delbaere, L. T. J. (1988) J. Biol. Chem. 263, 2571-2574). Single crystals up to 0.25 x 0.50 x 0.05 mm in size were grown by the technique of washing and reseeding. The space group is C2, with unit cell dimensions a = 130.0, b = 68.1, and c = 77.6 A; beta = 97.3 degrees; and Z = 4. There is one Fab-histidine-containing protein complex/asymmetric unit, and the solvent content is estimated to be 57%.