Structure at 4.5 Å; Resolution of a Phosphorylcholine-binding Fab

The electron density at 4.5 A resolution of the Fab' fragment of McPC603 mouse myeloma immunoglobulin with phosphorylcholine-binding activity can be divided into four distinct globular regions which are interpreted to correspond to the four domains in the molecule. The hapten-binding site was located by difference Fourier techniques and lies between two domains near one end of the...