CALCINEURIN-IMMUNOSUPPRESSOR COMPLEXES

Crystal structures of the Ser/Thr phosphatase calcineurin (protein pho sphatase 2B) have recently been solved by X-ray crystallography, both in the free-protein state, and complexed with the immunophilin/immunos uppressant FKBP12/FK506. Core elements of the calcineurin phosphatase have been found to be similar to the corresponding elements of Ser/Thr phosphatase 1 and purple acid phosphatase. The structures provide a b asis for understanding calcineurin inhibition by a ternary complex of immunophilin and immunosuppressant proteins.