The Role of Water Molecules in the Structure-Based Design of (5-Hydroxynorvaline)-2-Cyclosporin: Synthesis, Biological Activity, and Crystallographic Analysis with Cyclophilin A.Mikol, V., Papageorgiou, C., Borer, X.
(1995) J.Med.Chem. 38: 3361
- PubMed: 7650689
- PubMed Abstract:
- 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
Analysis of the contact surface of the cyclophilin A (CypA)/cyclosporin A (CsA, 1) crystal structure delineates a unique cavity between both molecules in the vicinity of the Abu-2 side chain atoms of 1 (Abu pocket). Therefore, (5-hydroxynorvaline)-2- ...
Analysis of the contact surface of the cyclophilin A (CypA)/cyclosporin A (CsA, 1) crystal structure delineates a unique cavity between both molecules in the vicinity of the Abu-2 side chain atoms of 1 (Abu pocket). Therefore, (5-hydroxynorvaline)-2-cyclosporin (2) was designed and prepared as a CsA derivative which could mediate additional interactions within the pocket. The X-ray crystal structure of the CypA/2 complex at 1.76 A resolution shows that 1 and 2 have identical backbone conformations and that the introduced hydroxypropyl chain makes indeed the expected supplemental interactions with CypA. However, 2 has 8-9-fold lower binding affinity than 1 for CypA. This results from a presumed unfavorable free energy change associated with the displacement of one of the tightly bound water molecules within the pocket and a change in prebinding equilibria. The role of the later was assessed by comparing the conformation distribution of 1 and 2 to that of norvaline-2-cyclosporin (3) and norvaline-2-(D-MeSer)-3-cyclosporin (4).
Sandoz Pharma Ltd., Preclinical Research, Basel, Switzerland.