APPLICATION OF C-13 NMR-SPECTROSCOPY TO PARATOPE MAPPING FOR LARGER ANTIGEN-FAB COMPLEXES

For the purpose of engineering the antibody combining site, mapping re sidues that are involved in antigen binding provide us with valuable i nformation. By use of C-13 NMR spectroscopy with selectively C-13-labe led Fv fragments, we have established a general strategy to identify t he residues that are perturbed upon binding of small antigen (hapten) molecules [(1990) Biochemistry 30, 6604-6610]. In the present paper, w e demonstrate that this strategy can be extended to molecular structur al analyses of the complexes of an Fab fragment and a larger antigen m olecule such as Pseudomonas aeruginosa exotoxin A with a molecular mas s of 67 kDa.