2DRU

Crystal structure and binding properties of the CD2 and CD244 (2B4) binding protein, CD48

Summary for 2DRU

• Entry DOI: 10.2210/pdb2dru/pdb
• Descriptor: chimera of CD48 antigen and T-cell surface antigen CD2, 2-acetamido-2-deoxy-beta-D-glucopyranose, GLYCEROL, ... (4 entities in total)
• Functional Keywords: cd2 binding domain of cd48, immune system
• Biological source: Rattus norvegicus (Norway rat); More
• Total number of polymer chains: 1
• Total formula weight: 22266.20

Authors

Evans, E.J.,Ikemizu, S.,Davis, S.J. (deposition date: 2006-06-15, release date: 2006-07-04, Last modification date: 2024-11-20)

Primary citation

Evans, E.J.,Castro, M.A.A.,O'Brien, R.,Kearney, A.,Walsh, H.,Sparks, L.M.,Tucknott, M.G.,Davies, E.A.,Carmo, A.M.,van der Merwe, P.A.,Stuart, D.I.,Jones, E.Y.,Ladbury, J.E.,Ikemizu, S.,Davis, S.J.
Crystal Structure and Binding Properties of the CD2 and CD244 (2B4)-binding Protein, CD48
J.Biol.Chem., 281:29309-29320, 2006

PubMed Abstract: The structural analysis of surface proteins belonging to the CD2 subset of the immunoglobulin superfamily has yielded important insights into transient cellular interactions. In mice and rats, CD2 and CD244 (2B4), which are expressed predominantly on T cells and natural killer cells, respectively, bind the same, broadly expressed ligand, CD48. Structures of CD2 and CD244 have been solved previously, and we now present the structure of the receptor-binding domain of rat CD48. The receptor-binding surface of CD48 is unusually flat, as in the case of rat CD2, and shares a high degree of electrostatic complementarity with the equivalent surface of CD2. The relatively simple arrangement of charged residues and this flat topology explain why CD48 cross-reacts with CD2 and CD244 and, in rats, with the CD244-related protein, 2B4R. Comparisons of modeled complexes of CD2 and CD48 with the complex of human CD2 and CD58 are suggestive of there being substantial plasticity in the topology of ligand binding by CD2. Thermodynamic analysis of the native CD48-CD2 interaction indicates that binding is driven by equivalent, weak enthalpic and entropic effects, in contrast to the human CD2-CD58 interaction, for which there is a large entropic barrier. Overall, the structural and biophysical comparisons of the CD2 homologues suggest that the evolutionary diversification of interacting cell surface proteins is rapid and constrained only by the requirement that binding remains weak and specific.

PubMed: 16803907
DOI: 10.1074/jbc.M601314200

Experimental method

X-RAY DIFFRACTION (2.6 Å)