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Hidden alternative structures of proline isomerase essential for catalysis

Abstract

A long-standing challenge is to understand at the atomic level how protein dynamics contribute to enzyme catalysis. X-ray crystallography can provide snapshots of conformational substates sampled during enzymatic reactions1, while NMR relaxation methods reveal the rates of interconversion between substates and the corresponding relative populations1,2. However, these current methods cannot simultaneously reveal the detailed atomic structures of the rare states and rationalize the finding that intrinsic motions in the free enzyme occur on a timescale similar to the catalytic turnover rate. Here we introduce dual strategies of ambient-temperature X-ray crystallographic data collection and automated electron-density sampling to structurally unravel interconverting substates of the human proline isomerase, cyclophilin A (CYPA, also known as PPIA). A conservative mutation outside the active site was designed to stabilize features of the previously hidden minor conformation. This mutation not only inverts the equilibrium between the substates, but also causes large, parallel reductions in the conformational interconversion rates and the catalytic rate. These studies introduce crystallographic approaches to define functional minor protein conformations and, in combination with NMR analysis of the enzyme dynamics in solution, show how collective motions directly contribute to the catalytic power of an enzyme.

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Figure 1: Room-temperature X-ray crystallography and Ringer analysis detect conformational substates in CYPA.
Figure 2: The structure of the Ser99Thr mutant resembles the minor conformer of wild-type CYPA.
Figure 3: The Ser99Thr mutation shifts the equilibrium towards the minor wild-type conformation and slows motions in the dynamic network in free CYPA.
Figure 4: Impeded motions in the dynamic network severely reduce the catalytic power of a chemically competent enzyme.

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Primary accessions

Protein Data Bank

Data deposits

Atomic coordinates and structure factors for the reported crystal structures have been deposited in the PDB under accession codes 3K0M, 3K0N, 3K0O, 3K0P, 3K0Q and 3K0R.

References

  1. Henzler-Wildman, K. & Kern, D. Dynamic personalities of proteins. Nature 450, 964–972 (2007)

    Article  CAS  ADS  Google Scholar 

  2. Mittermaier, A. & Kay, L. E. Review—new tools provide new insights in NMR studies of protein dynamics. Science 312, 224–228 (2006)

    Article  CAS  ADS  Google Scholar 

  3. Boehr, D. D., McElheny, D., Dyson, H. J. & Wright, P. E. The dynamic energy landscape of dihydrofolate reductase catalysis. Science 313, 1638–1642 (2006)

    Article  CAS  ADS  Google Scholar 

  4. Eisenmesser, E. Z. et al. Intrinsic dynamics of an enzyme underlies catalysis. Nature 438, 117–121 (2005)

    Article  CAS  ADS  Google Scholar 

  5. Hammes-Schiffer, S. & Benkovic, S. J. Relating protein motion to catalysis. Annu. Rev. Biochem. 75, 519–541 (2006)

    Article  CAS  Google Scholar 

  6. Schramm, V. L. & Shi, W. Atomic motion in enzymatic reaction coordinates. Curr. Opin. Struct. Biol. 11, 657–665 (2001)

    Article  CAS  Google Scholar 

  7. Agarwal, P. K. Cis/trans isomerization in HIV-1 capsid protein catalyzed by cyclophilin A: insights from computational and theoretical studies. Proteins 56, 449–463 (2004)

    Article  CAS  Google Scholar 

  8. Hamelberg, D. & McCammon, A. Mechanistic insight into the role of transition-state stabilization in cyclophilin A. J. Am. Chem. Soc. 131, 147–152 (2009)

    Article  CAS  Google Scholar 

  9. Li, G. H. & Cui, Q. What is so special about Arg 55 in the catalysis of cyclophilin A? Insights from hybrid QM/MM simulations. J. Am. Chem. Soc. 125, 15028–15038 (2003)

    Article  CAS  Google Scholar 

  10. Trzesniak, D. & Van Gunsteren, W. F. Catalytic mechanism of cyclophilin as observed in molecular dynamics simulations: pathway prediction and reconciliation of X-ray crystallographic and NMR solution data. Protein Sci. 15, 2544–2551 (2006)

    Article  CAS  Google Scholar 

  11. Howard, B. R., Vajdos, F. F., Li, S., Sundquist, W. I. & Hill, C. P. Structural insights into the catalytic mechanism of cyclophilin A. Nature Struct. Biol. 10, 475–481 (2003)

    Article  CAS  Google Scholar 

  12. Ke, H. M. & Huai, Q. Crystal structures of cyclophilin and its partners. Front. Biosci. 9, 2285–2296 (2004)

    Article  CAS  Google Scholar 

  13. Lang, P. T. et al. Automated electron-density sampling reveals widespread conformational polymorphism in proteins. Protein Sci. (submitted)

  14. Eisenmesser, E. Z., Bosco, D. A., Akke, M. & Kern, D. Enzyme dynamics during catalysis. Science 295, 1520–1523 (2002)

    Article  CAS  ADS  Google Scholar 

  15. Halle, B. Biomolecular cryocrystallography: structural changes during flash-cooling. Proc. Natl Acad. Sci. USA 101, 4793–4798 (2004)

    Article  CAS  ADS  Google Scholar 

  16. Rasmussen, B. F., Stock, A. M., Ringe, D. & Petsko, G. A. Crystalline ribonuclease A loses function below the dynamical transition at 220 K. Nature 357, 423–424 (1992)

    Article  CAS  ADS  Google Scholar 

  17. Loria, J. P., Rance, M. & Palmer, A. G. A TROSY CPMG sequence for characterizing chemical exchange in large proteins. J. Biomol. NMR 15, 151–155 (1999)

    Article  CAS  Google Scholar 

  18. Millet, O., Loria, J. P., Kroenke, C. D., Pons, M. & Palmer, A. G. The static magnetic field dependence of chemical exchange linebroadening defines the NMR chemical shift time scale. J. Am. Chem. Soc. 122, 2867–2877 (2000)

    Article  CAS  Google Scholar 

  19. Kofron, J. L., Kuzmic, P., Kishore, V., Colonbonilla, E. & Rich, D. H. Determination of kinetic constants for peptidyl prolyl cis-trans isomerases by an improved spectrophotometric assay. Biochemistry 30, 6127–6134 (1991)

    Article  CAS  Google Scholar 

  20. Farrow, N. A., Zhang, O. W., Forman-Kay, J. D. & Kay, L. E. A Heteronuclear correlation experiment for simultaneous determination of 15N longitudinal decay and chemical exchange rates of systems in slow equilibrium. J. Biomol. NMR 4, 727–734 (1994)

    Article  CAS  Google Scholar 

  21. Zydowsky, L. D. et al. Active site mutants of human cyclophilin A separate peptidyl-prolyl isomerase activity from cyclosporine A binding and calcineurin inhibition. Protein Sci. 1, 1092–1099 (1992)

    Article  CAS  Google Scholar 

  22. Frauenfelder, H. et al. Thermal expansion of a protein. Biochemistry 26, 254–261 (1987)

    Article  CAS  Google Scholar 

  23. Frauenfelder, H., Petsko, G. A. & Tsernoglou, D. Temperature-dependent X-ray diffraction as a probe of protein structural dynamics. Nature 280, 558–563 (1979)

    Article  CAS  ADS  Google Scholar 

  24. Tilton, R. F., Dewan, J. C. & Petsko, G. A. Effects of temperature on protein structure and dynamics: X-ray crystallographic studies of the protein ribonuclease-A at nine different temperatures from 98 to 320K. Biochemistry 31, 2469–2481 (1992)

    Article  CAS  Google Scholar 

  25. Beach, H., Cole, R., Gill, M. L. & Loria, J. P. Conservation of μs-ms enzyme motions in the apo- and substrate-mimicked state. J. Am. Chem. Soc. 127, 9167–9176 (2005)

    Article  CAS  Google Scholar 

  26. Tokuriki, N. & Tawfik, D. S. Protein dynamism and evolvability. Science 324, 203–207 (2009)

    Article  CAS  ADS  Google Scholar 

  27. Lee, G. M. & Craik, C. S. Trapping moving targets with small molecules. Science 324, 213–215 (2009)

    Article  CAS  ADS  Google Scholar 

  28. Kiefersauer, R. et al. A novel free-mounting system for protein crystals: transformation and improvement of diffraction power by accurately controlled humidity changes. J. Appl. Crystallogr. 33, 1223–1230 (2000)

    Article  CAS  Google Scholar 

  29. Davis, D. G., Perlman, M. E. & London, R. E. Direct measurements of the dissociation-rate constant for inhibitor-enzyme complexes via the T 1ρ and T 2(CPMG) methods. J. Magn. Reson. Ser. B 104, 266–275 (1994)

    Article  CAS  Google Scholar 

  30. Hu, J. S., Grzesiek, S. & Bax, A. Two-dimensional NMR methods for determining χ1 angles of aromatic residues in proteins from three-bond JC'Cγ and JNCγ couplings. J. Am. Chem. Soc. 119, 1803–1804 (1997)

    Article  CAS  Google Scholar 

  31. Southworth-Davies, R. J., Medina, M. A., Carmichael, I. & Garman, E. F. Observation of decreased radiation damage at higher dose rates in room temperature protein crystallography. Structure 15, 1531–1541 (2007)

    Article  CAS  Google Scholar 

  32. Otwinowski, Z. & Minor, W. in Macromolecular Crystallography Part A 307–326 (Methods in Enzymology, Vol. 276, Academic, 1997)

    Book  Google Scholar 

  33. McCoy, A. J. et al. Phaser crystallographic software. J. Appl. Crystallogr. 40, 658–674 (2007)

    Article  CAS  Google Scholar 

  34. Adams, P. D. et al. PHENIX: building new software for automated crystallographic structure determination. Acta Crystallogr. D 58, 1948–1954 (2002)

    Article  Google Scholar 

  35. Holton, J. & Alber, T. Automated protein crystal structure determination using ELVES. Proc. Natl Acad. Sci. USA 101, 1537–1542 (2004)

    Article  CAS  ADS  Google Scholar 

  36. Kabsch, W. Automatic processing of rotation diffraction data from crystals of initially unknown symmetry and cell constants. J. Appl. Crystallogr. 26, 795–800 (1993)

    Article  CAS  Google Scholar 

  37. Emsley, P. & Cowtan, K. Coot: model-building tools for molecular graphics. Acta Crystallogr. D 60, 2126–2132 (2004)

    Article  Google Scholar 

  38. Davis, I. W. et al. MolProbity: all-atom contacts and structure validation for proteins and nucleic acids. Nucleic Acids Res. 35, W375–W383 (2007)

    Article  ADS  Google Scholar 

  39. Laskowski, R. A., Macarthur, M. W., Moss, D. S. & Thornton, J. M. Procheck—a program to check the stereochemical quality of protein structures. J. Appl. Crystallogr. 26, 283–291 (1993)

    Article  CAS  Google Scholar 

  40. Delano, W. L. The PyMOL Molecular Graphics System (DeLano Scientific, Palo Alto, 2008); 〈http://www.pymol.org

  41. Theobald, D. L. & Wuttke, D. S. THESEUS: maximum likelihood superpositioning and analysis of macromolecular structures. Bioinformatics 22, 2171–2172 (2006)

    Article  CAS  Google Scholar 

  42. Mulder, F. A. A., Mittermaier, A., Hon, B., Dahlquist, F. W. & Kay, L. E. Studying excited states of proteins by NMR spectroscopy. Nature Struct. Biol. 8, 932–935 (2001)

    Article  CAS  Google Scholar 

  43. Delaglio, F. et al. NMRPipe—a multidimensional spectral processing system based on UNIX pipes. J. Biomol. NMR 6, 277–293 (1995)

    Article  CAS  Google Scholar 

  44. Johnson, B. A. & Blevins, R. A. NMR View—a computer program for the visualization and analysis of NMR data. J. Biomol. NMR 4, 603–614 (1994)

    Article  CAS  Google Scholar 

  45. Jeener, J., Meier, B. H., Bachmann, P. & Ernst, R. R. Investigation of exchange processes by 2-dimensional NMR-spectroscopy. J. Chem. Phys. 71, 4546–4553 (1979)

    Article  CAS  ADS  Google Scholar 

Download references

Acknowledgements

We thank S. Marqusee and B. Krantz for discussions; S. Classen, G. Meigs, J. Holton, A. Samelson, N. Echols, P. Afonine, and the Phenix team for technical support; J. Tainer for access to Rigaku free-mounting device at ALS Beamline 12.3.1; J. Pelton and D. Wemmer for providing essential help and access to NMR facilities. J.S.F. was supported by US NSF and Canadian NSERC fellowships. This work was funded by the US National Institutes of Health (to T.A.) and the US National Institutes of Health, the US Department of Energy Office of Basic Energy Sciences, and the Howard Hughes Medical Institute (to D.K.).

Author Contributions J.S.F., S.C.D. and R.E. performed the X-ray experiments, M.W.C. performed the NMR experiments, and M.W.C. and J.S.F. performed the activity and binding assays. J.S.F., M.W.C., D.K. and T.A. analysed data and wrote the paper. All authors contributed to data interpretation and commented on the manuscript.

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Correspondence to Dorothee Kern or Tom Alber.

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Fraser, J., Clarkson, M., Degnan, S. et al. Hidden alternative structures of proline isomerase essential for catalysis . Nature 462, 669–673 (2009). https://doi.org/10.1038/nature08615

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