Crystallization of a soluble form of the rat T-cell surface glycoprotein CD4 complexed with Fab from the W3/25 monoclonal antibody

Davis SJ, Brady RL, Barclay AN, Harlos K, Dodson GG, Williams AF. (1990), J Mol Biol. 213, 7-10

Abstract

The structure of the T-lymphocyte cell surface glycoprotein CD4 is of considerable biological and medical interest. Recombinant rat CD4 expressed in soluble form in mammalian cells and complexed with W3/25 monoclonal Fab fragments formed crystals that diffract to 3·5 Å and have the orthorhombic space group P2₁2₁2 or P2₁2₁2₁. The unit cell has dimensions a = 317 Å, b = 161 Å and c = 41·8 Å and the asymmetric unit consists of two CD4 : Fab complexes. These crystals are of suitable quality for X-ray diffraction analysis.

Key figure: Crystals of a soluble form of rat CD4 (sCD4) complexed with Fab from the W3/25 monoclonal antibody

(a) Representative crystals; the dimensions of these crystals are approximately 0.3 mm x 0.2 mm x 0.1 mm. (b) SDS/polyacrylamide gel electrophoresis analysis of the crystals in reducing conditions: lane 1, 5 μg of purified W3/25 Fab; lane 2, 5 μg of sCD4 purified by ion-exchange chromatography; lane 3, 10 μg of the complex used for the crystallization trials; lanes 4 and 5, 10 μg and 2 μg of protein from the washed and redissolved crystals, respectively.