Journal of Biomolecular NMR

, Volume 4, Issue 4, pp 463–482

Determination of the NMR solution structure of the cyclophilin A-cyclosporin A complex

Authors

  • C. Spitzfaden
    • Institut für Molekularbiologie und BiophysikEidgenössische Technische Hochschule-Hönggerberg
  • W. Braun
    • Institut für Molekularbiologie und BiophysikEidgenössische Technische Hochschule-Hönggerberg
  • G. Wider
    • Institut für Molekularbiologie und BiophysikEidgenössische Technische Hochschule-Hönggerberg
  • H. Widmer
    • Preclinical ResearchSandoz Pharma Ltd.
  • K. Wüthrich
    • Institut für Molekularbiologie und BiophysikEidgenössische Technische Hochschule-Hönggerberg
Research Papers

DOI: 10.1007/BF00156614

Cite this article as:
Spitzfaden, C., Braun, W., Wider, G. et al. J Biomol NMR (1994) 4: 463. doi:10.1007/BF00156614
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Summary

The three-dimensional NMR solution structure of the cyclophilin A (Cyp)-cyclosporin A (CsA) complex was determined, and here we provide a detailed description of the analysis of the NMR data and the structure calculation. Using 15N-and 13C-resolved three- and four-dimensional [1H, 1H]-nuclear Overhauser enhancement (NOE) spectroscopy with uniformly isotope-labeled Cyp in the complex, a final data set of 1810 intra-Cyp, 107 intra-CsA and 63 intermolecular NOE upper distance constraints was collected as input for the structure calculation with the program DIANA. A group of DIANA conformers, selected by a previously described analysis of the dependence of the maximal root-mean-square deviation (rmsd) among the individual conformers on the residual target function value, was subjected to energy refinement with the program FANTOM. The 22 best energy-refined conformers were then used to represent the solution structure. The average rmsd relative to the mean structure of these 22 conformers is 1.1 Å for the backbone atoms of all residues of the complex. The molecular architecture of Cyp in the Cyp-CsA complex includes an eight-stranded antiparallel β-barrel, which is closed on each side by an amphipathic helix. CsA is bound in a cavity formed by part of the barrel surface and four loops with nonregular secondary structure. Comparison of this structure with structures of Cyp-CsA and other Cyp-peptide complexes determined by different approaches shows extensive similarities.

Keywords

Cyclosporin ACyclophilinImmune suppressionNMR structureDrug-receptor interaction
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© ESCOM Science Publishers B.V 1994