Title : Crystal structure of the extracellular
region of the human cell adhesion molecule
CD2 at 2.5 A resolution
Abstract :
- BACKGROUND: The T-lymphocyte antigen CD2 is an adhesion molecule implicated in immune responses in vivo
- The extracellular regions of the human and rat homologues of CD2 share only 45% sequence identity and bind different protein ligands
- Comparison of the human and rat soluble CD2 ( sCD2 ) structures should provide insights into the structural basis of cell surface recognition
- RESULTS: We therefore determined the crystal structure of a form of human sCD2 with single N-acetylglucosamine residues at each glycosylation site to 2.5 A resolution with an R-factor of 19.3%
- It is composed of two immunoglobulin superfamily domains similar to those of rat sCD2 , but the relative orientation of the domains in the two homologues differs by up to 20 degrees
- An interaction involving the flat, highly charged, ligand binding GFCC'C" faces of crystallographically related human sCD2 molecules duplicates, in a different lattice, that observed in the rat sCD2 crystals
- CONCLUSIONS: Intramolecular flexibility appears to be a conserved feature of CD2
- The head-to-head interaction between molecules represents a general model for interactions between adhesion molecules of this structural class
- Ligand specificity may be influenced by the distribution of charged residues on the binding face
Output (sent_index, trigger,
protein,
sugar,
site):
- 4. glycosylation, , -, -, site
Output(Part-Of) (sent_index,
protein,
site):
*Output_Site_Fusion* (sent_index,
protein,
sugar,
site):