Refined crystal structure of a recombinant immunoglobulin domain and a complementarity-determining region 1-grafted mutant.

Steipe B; Pluckthun A; Huber R

Abteilung Strukturforschung, Max-Planck-Institut fur Biochemie, Martinsried, Germany.

J Mol Biol 225: 739-53 (1992)

Abstract
We report the solution of the crystal structure of a mutant of the immunoglobulin VL domain of the antibody McPC603, in which the complementarity-determining region 1 segment is replaced with that of a different antibody. The wild-type and mutant crystal structures have been refined to a crystallographic R-factor of 14.9% at a nominal resolution of 1.97 A. A detailed description of the structures is given. Crystal packing results in a dimeric association of domains, in a fashion closely resembling that of an Fv fragment. The comparison of this VL domain with the same domain in the Fab fragment of McPC603 shows that the structure of an immunoglobulin VL domain is largely independent of its mode of association, even in places where the inter-subunit contacts are not conserved between VL and VH. In all three complementarity-determining regions we observe conformations that would not have been predicted by the canonical structure hypothesis. Significant differences between the VL domain dimer and the Fab fragment in the third complementarity-determining region show that knowledge of the structure of the dimerization partner and its exact mode of association may be needed to predict the precise conformation of antigen-binding loops.

Mesh Headings

Amino Acid Sequence
Animal
Asparagine
Crystallography
Disulfides
Glutamine
Hydrogen Bonding
Immunoglobulin Variable Region*
Immunoglobulins, kappa-Chain*
Immunoglobulins, Fab
In Vitro
Mice
Models, Molecular
Molecular Sequence Data
Protein Conformation
Recombinant Fusion Proteins
X-Ray Diffraction

Unique Identifier: 92292158

Chemical Identifiers (Names)

(Immunoglobulin Variable Region)
(Immunoglobulins, kappa-Chain)
(Immunoglobulins, Fab)
(Recombinant Fusion Proteins)
6899-04-3 (Glutamine)
7006-34-0 (Asparagine)