THE CONTRIBUTION OF CONFORMATIONAL ADJUSTMENTS AND LONG-RANGE ELECTROSTATIC FORCES TO THE CD2/CD58 INTERACTION

摘要

CD2 is a T cell surface molecule that enhances T and Natural Killer cell function by binding its ligands CD58 (humans) and CD48 (rodents) on antigen presenting or target cells. Here we show that the CD2/CD58 interaction is enthalpically-driven and accompanied by unfavourable entropic changes. Taken together with structural studies, this indicates that binding is accompanied by energetically-significant conformational adjustments. Despite having a highly charged binding interface neither the affinity nor rate constants of the CD2/CD58 interaction were affected by changes in ionic strength, indicating that long-range electrostatic forces make no net contribution to binding.