Download MendeleyThe 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
- DOI: https://doi.org/10.1021/jm00017a020
- Primary Citation of Related Structures:
1MIK - PubMed Abstract:
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).
Organizational Affiliation:
Sandoz Pharma Ltd., Preclinical Research, Basel, Switzerland.
