The X-Ray Structure of (Mebm2T)1-Cyclosporin Complexed with Cyclophilin a Provides an Explanation for its Anomalously High Immunosuppressive Activity.Mikol, V., Kallen, J., Walkinshaw, M.D.
(1994) Protein Eng. 7: 597
- PubMed: 8073029
- Also Cited By: 1CWA, 1CWC
- PubMed Abstract:
- X-Ray Structure of a Decameric Cyclophilin- Cyclosporin Crystal Complex.
Pflugl, G.,Kallen, J.,Schirmer, T.,Jansonius, J.N.,Zurini, M.G.,Walkinshaw, M.D.
(1993) Nature 361: 91
- Crystallization of the Complex between Cyclophilin a and Cyclosporin Derivatives: The Use of Cross- Seeding.
Mikol, V.,Duc, D.
(1994) Acta Crystallogr.,Sect.D 50: 543
- X-Ray Structure of a Monomeric Cyclophilin A- Cyclosporin a Crystal Complex at 2.1 A Resolution.
Mikol, V.,Kallen, J.,Pflugl, G.,Walkinshaw, M.D.
(1993) J.Mol.Biol. 234: 1119
- Improved Binding Affinity for Cyclophilin a by a Cyclosporin Derivative Singly Modified at its Effector Domain.
Papageorgiou, C.,Florineth, A.,Mikol, V.
(1994) J.Med.Chem. 37: 3674
For most of the cyclosporin A (CsA) analogs, there is generally a good correlation between cyclophilin binding and immunosuppression. However, this relationship does not seem to hold for 4-[(E)-2-butenyl]-4,4,N-trimethyl-L-threonine1 (MeBm2t)1-CsA. I ...
For most of the cyclosporin A (CsA) analogs, there is generally a good correlation between cyclophilin binding and immunosuppression. However, this relationship does not seem to hold for 4-[(E)-2-butenyl]-4,4,N-trimethyl-L-threonine1 (MeBm2t)1-CsA. Its affinity for cyclophilin was reported to be approximately 1% that of CsA and its immunosuppressive activity in vitro was shown to be approximately 30% that of CsA. We report here the crystal structure of a complex between recombinant human cyclophilin A (CypA) and (MeBm2t)1-CsA which has been determined by X-ray crystallography at 2.2 A resolution and refined to an R-factor of 16.3%. (MeBm2t)1-CsA shows a similar bound conformation and network of interactions to CypA as CsA. The measured lower affinity for CypA cannot therefore be explained by a different mode of binding. We propose that the poor affinity to CypA could be accounted for by the existence of an equilibrium in aqueous solution between a 'cyclophilin bound conformation' and a 'non-binding conformation' of (MeBm2t)1-CsA. The relatively high immunosuppressive activity is suggested to result from slight conformational differences observed in the effector domain.
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