CRYSTALLIZATION AND PRELIMINARY-X-RAY DIFFRACTION STUDIES OF A MONOCLONAL-ANTIBODY FAB FRAGMENT AGAINST FOOT-AND-MOUTH-DISEASE VIRUS AND OFITS COMPLEX WITH THE MAIN ANTIGENIC SITE PEPTIDE

The Fab fragment of the neutralizing monoclonal antibody SD6 elicited against foot-and-mouth disease virus (FMDV) C-S8c1 and its complex wit h a peptide, corresponding to the major antigenic site of FMDV (VP1 re sidues 136-150, YTASARGDLAHLTTT), have been crystallized using the han ging drop vapor diffusion techniques. For the isolated Fab, crystals d iffracting to 2.5 Angstrom resolution were obtained at room temperatur e using ammonium sulfate as precipitant. These crystals are monoclinic , space group C2, and unit cell parameters alpha = 109.53 Angstrom, b = 89.12 Angstrom, c = 64.04 Angstrom, and beta = 112.9 degrees and con tain one Feb molecule per asymmetric unit. Crystals from the complex d iffract, at least, to 2.8 Angstrom resolution and were obtained, at ro om temperature, using PEG as precipitant. These crystals are monoclini c, space group P2, and unit cell parameters alpha 56.11 Angstrom, b = 60.67 Angstrom, c = 143.45 Angstrom, and beta = 95.4 degrees. Density packing considerations indicate that there are two Fab molecules in th e asymmetric unit. (C) 1994 Wiley-Liss, Inc.