Three-dimensional structure of murine anti-p-azophenylarsonate Fab 36-71. 1. X-ray crystallography, site-directed mutagenesis, and modeling of the complex with hapten.Strong, R.K., Campbell, R., Rose, D.R., Petsko, G.A., Sharon, J., Margolies, M.N.
(1991) Biochemistry 30: 3739-3748
- PubMed: 2015229
- Primary Citation of Related Structures:
- PubMed Abstract:
- Amino Acid Sequence of the Variable Region of the Light (Lambda) Chain from Human Myeloma Cryoimmunoglobulin Igg Hil
Lopez De Castro, J.A.,Chiu, Y.-Y.H.,Poljak, R.J.
(1978) Biochemistry 17: 1718
- Amino Acid Sequence of the VH Region of Human Myeloma Cryoimmunoglobulin Igg Hil
Chiu, Y.-Y.H.,Lopez De Castro, J.A.,Poljak, R.J.
(1979) Biochemistry 18: 553
- Crystals of Fragment Fab': Preparation from Pepsin Digests of Human Igg Myeloma Proteins
Rossi, G.,Choi, T.K.,Nisonoff, A.
(1969) Nature 223: 837
The structure of the antigen-binding fragment (Fab) of an anti-p-azophenylarsonate monoclonal antibody, 36-71, bearing a major cross-reactive idiotype of A/J mice has been refined to an R factor of 24.8% at a resolution of 1.85 A. The previously solv ...
The structure of the antigen-binding fragment (Fab) of an anti-p-azophenylarsonate monoclonal antibody, 36-71, bearing a major cross-reactive idiotype of A/J mice has been refined to an R factor of 24.8% at a resolution of 1.85 A. The previously solved partial structure of this Fab at a resolution of 2.9 A (Rose et al., 1990) was used as an initial model for refinement against the high-resolution data. The complex with hapten has been modeled by docking the small-molecule crystal structure of phenylarsonic acid into the structure of the native Fab on the basis of a low-resolution electron density map of the complex. In this model, residue Arg-96 in the light chain and residues Asn-35, Trp-47, and Ser-99 in the heavy chain contact the arsonate moiety of the hapten; an additional bond is found between the arsonate group and a tightly bound water molecule. The phenyl moiety of the hapten packs against two tyrosine side chains at positions 50 and 106 in the heavy chain. Residue Arg-96 in the light chain had been implicated as involved in hapten binding on the basis of previous experiments, and indeed, this residue appears to play a crucial role in this model. Experiments employing site-directed mutagenesis directly support this conclusion. The heavy-chain complementarity-determining regions have novel conformations not previously observed in immunoglobulins except for the recently solved anti-p-azophenylarsonate Fab R 19.9 (Lascombe et al., 1989).
California Institute of Technology, Pasadena 91125.