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Millisecond Laue structures of an enzyme–product complex using photocaged substrate analogs

Abstract

The structure of a rate-limited product complex formed during a single initial round of turnover by isocitrate dehydrogenase has been determined. Photolytic liberation of either caged substrate or caged cofactor and Laue X-ray data collection were used to visualize the complex, which has a minimum half-life of approximately 10 milliseconds. The experiment was conducted with three different photoreactive compounds, each possessing a unique mechanism leading to the formation of the enzyme–substrate (ES) complex. Photoreaction efficiency and subsequent substrate affinities and binding rates in the crystal are critical parameters for these experiments. The structure suggests that CO2 dissociation is a rapid event that may help drive product formation, and that small conformational changes may contribute to slow product release .

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Figure 1: a, General kinetic mechanism of isocitrate dehdyrogenase.
Figure 2: Chemical structures of the three caged substrate analogs used in this study.
Figure 3: Fo - Fc difference maps after initial protein refinement against merged Laue data, displayed over the substrate/product binding site.
Figure 4: Superimposed structures of product complex (blue) and protein side chains from the initial refinement model (isocitrate–NADP+ complex, red).

References

  1. Moffat, K. Laue Diffraction. Meth. Enz. 277, 433– 447 (1997).

    Article  CAS  Google Scholar 

  2. Stoddard, B. L. Caught in a chemical trap. Nature Struct. Biol. 3, 907–909 (1996).

    Article  CAS  Google Scholar 

  3. Stoddard, B. L. Intermediate trapping and Laue X-ray diffraction: potential for enzyme mechanism, dynamics, and inhibitor screening. Pharmacol. Thera. 70, 215–256 (1996).

    Article  CAS  Google Scholar 

  4. Moffat, K. & Ren, Z. Synchrotron radiation applications to macromolecular crystallography. Curr. Opin. Struct. Biol. 7, 689–696 (1997).

    Article  CAS  Google Scholar 

  5. Perman, B., et al. Energy transduction on the nanosecond time scale: early structural events in a xanthopsin photocycle. Science 279, 1946–1950 (1998).

    Article  CAS  Google Scholar 

  6. Szebenyi, D. M. E. et al. Quantitative analysis of Laue diffraction patterns recorded with a 120 picosecond exposure from an X-ray undulator. Trans. Am. Crystall. 24, 167–172 (1988).

    Google Scholar 

  7. Srajer,V. et al. Photolysis of the carbon monoxide complex of myoglobin: nanosecond time-resolved crystallography. Science 274, 1726–1729 (1996).

    Article  CAS  Google Scholar 

  8. Genick, U. K. et al. Structure of a protein photocycle intermediate by millisecond time-resolved crystallography. Science 275, 1471–1475 (1997).

    Article  CAS  Google Scholar 

  9. Teng, T. Y., Srajer,V. & Moffat, K. Initial trajectory of carbon monoxide after photodissociation from myoglobin at cryogenic temperatures. Biochemistry 36, 12087–12100 (1997).

    Article  CAS  Google Scholar 

  10. Farber, G. K. Laue crystallography: Lights! Camera! Action! Curr. Biol. 7, R352–R354 (1997).

    Article  CAS  Google Scholar 

  11. Imamoto, Y., Kataoka, M. & Tokunaga, F. Photoreaction cycle of photoactive yellow protein from Ectothiorhodospira halophila studied by low-temperature spectroscopy. Biochemistry 35, 14047–14053 (1996).

    Article  CAS  Google Scholar 

  12. Ng, K., Getzoff, E. D. & Moffat, K. Optical studies of a bacterial photoreceptor protein, photoactive yellow protein, in single crystals. Biochemistry 34, 879–889 (1995).

    Article  CAS  Google Scholar 

  13. Teng, T.-Y., Srajer,V. & Moffat, K. Photolysis-induced structural changes in single crystals of carbonmonoxy myoglobin at 40 K. Nature Struct. Biol. 1, 701–705 (1994).

    Article  CAS  Google Scholar 

  14. Genick, U. K., Soltis, S. M., Kuhn, P., Canestrelli, I. L. & Getzoff, E. D. Structure at 0.85 Å resolution of an early protein photocycle intermediate. Nature 392, 206–209 (1998).

    Article  CAS  Google Scholar 

  15. Schlichting, I., Berendzen, J., Phillips, G. N. P. Jr. & Sweet, R. M. Crystal structure of photolysed carbonmonoxy-myoglobin . Nature 371, 808–812 (1994).

    Article  CAS  Google Scholar 

  16. Schlichting, I. & Goody, R. S. Triggering methods in crystallographic enzyme kinetics. Meth. Enz. 277 , 467–490 (1997).

    Article  CAS  Google Scholar 

  17. Corrie, J. E. T., Katayama, Y., Reid, G. P., Anson, M. & Trentham, D. R. The development and application of photosensitive caged compounds to aid time-resolved structure determination of macromolecules. Phil. Trans. R. Soc. Lond. A 340 , 233–244 (1992).

    Article  CAS  Google Scholar 

  18. Stoddard, B. L., Koenigs, P., Porter, N., Petratos, K., Petsko, G. A. & Ringe, D. Observation of the light-triggered binding of pyrone to chymotrypsin by Laue X-ray crystallography. Proc. Natl. Acad. Sci. USA 88 , 5503–5507 (1991).

    Article  CAS  Google Scholar 

  19. Schlichting, I. et al. Time-resolved X-ray crystallographic study of the conformational change in Ha-Ras p21 protein on GTP hydrolysis. Nature 345, 309–315 (1990).

    Article  CAS  Google Scholar 

  20. Singer, P. T., Smalas, A., Carty, R. P., Mangel, W. F. & Sweet, R. M. The hydrolytic water molecule in trypsin, revealed by time-resolved Laue crystallography. Science 259, 669–673 (1993).

    Article  CAS  Google Scholar 

  21. Duke, E. M. H., Wakatsuki, W., Hadfield, A. & Johnson, L. N. Laue and monochromatic diffraction studies on catalysis in phosphorylase b crystals. Prot. Sci. 3, 1178– 1196 (1994).

    Article  CAS  Google Scholar 

  22. Hajdu, J. et al. Catalysis in the crystal: synchrotron radiation studies with glycogen phosphorylase b. EMBO J. 6, 539 –546 (1987).

    Article  CAS  Google Scholar 

  23. Stoddard, B. L. & Farber, G. K. Direct measurement of reactivity in the protein crystal by steady-state kinetic studies. Structure 3, 991–996 ( 1995).

    Article  CAS  Google Scholar 

  24. Hurley, J. H. et al. Structure of a bacterial enzyme regulated by phosphorylation, isocitrate dehdyrogenase. Proc. Natl. Acad. Sci. USA 86, 8635–8639 (1989).

    Article  CAS  Google Scholar 

  25. Hurley, J. H., Dean, A. M., Sohl, J. L., Koshland, D. E. & Stroud, R. M. Regulation of an enzyme by phosphorylation at the active site. Science 249, 1012– 1016 (1990).

    Article  CAS  Google Scholar 

  26. Hurley, J. H., Dean, A. M., Thorsness, P. E., Koshland, K. E. & Stroud, R. M. Regulation of isocitrate dehydrogenase by phosphorylation involves no long-range conformational change in the free enzyme. J. Biol. Chem. 265, 3599– 3602 (1990).

    CAS  PubMed  Google Scholar 

  27. Hurley, J. H., Dean, A. M., Koshland, D. E. & Stroud, R. M. Catalytic mechanism of NADP-dependent isocitrate dehydrogenase: implications from the structures of magnesium-isocitrate and NADP complexes. Biochemistry 30, 8671–8678 (1991).

    Article  CAS  Google Scholar 

  28. Bolduc, J. M. et al. Mutagenesis and Laue structures of enzyme intermediates: isocitrate dehydrogenase. Science 268, 1312 –1318 (1995).

    Article  CAS  Google Scholar 

  29. Stoddard, B. L., Dean, A. & Bash, P. A. Combining Laue diffraction and molecular dynamics to study enzyme intermediates. Nature Struct. Biol. 3, 590–595 (1996).

    Article  CAS  Google Scholar 

  30. Mesecar, A. D., Stoddard, B. L. & D. E. Koshland, J. Orbital steering in the catalytic power of enzymes: small structural changes with large catalytic consequences. Science 277, 202–206 ( 1997).

    Article  CAS  Google Scholar 

  31. Cohen, B. E., Stoddard, B. L. & D. E. Koshland, J. Caged NADP and NAD. Synthesis and characterization of functionally distinct caged compounds. Biochemistry 36, 9035–9044 (1997).

    Article  CAS  Google Scholar 

  32. Brubaker, M. J., Dyer, D. H., Stoddard, B. & D. E. Koshland, J. Synthesis, kinetics, and structural studies of a photolabile caged isocitrate: a catalytic trigger for isocitrate dehydrogenase. Biochemistry 35, 2854–2864 ( 1996).

    Article  CAS  Google Scholar 

  33. Dean, A. M. & Koshland, D. E. Kinetic mechanism of Escherichia coli isocitrate dehydrogenase. Biochemistry 32, 9302–9309 (1993).

    Article  CAS  Google Scholar 

  34. Stoddard, B. L. & D. E. Koshland, J. Structure of isocitrate dehydrogenase with α-ketoglutarate at 2.7 Å resolution: conformational chances induced by decarboxylation of isocitrate. Biochemistry 32, 9317–9322 (1993).

    Article  CAS  Google Scholar 

  35. Ottl, J., Gabriel, D. & Marriott, G. Preparation and Photoactivation Of Caged luorophores and Caged Proteins Using a New Class Of Heterobifunctional, Photocleavable Cross-Linking Reagents. Bioconjugate Chem. 9, 143-151 (1998).

    Article  CAS  Google Scholar 

  36. Getzoff, E. D., et al. Laue diffraction protein crystallography at the National Synchrotron Light Source. Nuclear Instr. Meth. Phys. Res. B 79, 249–255 (1993).

    Article  Google Scholar 

  37. Rapp, G. & Guth, K. A low cost high intensity flash device for photolysis experiments. Pflugers Arch (European J. of Phys.) 411, 200–203 ( 1988).

    Article  CAS  Google Scholar 

  38. Clifton, I. J., Duke, E. M. H., Wakatsuki, S. & Ren, Z. Evaluation of Laue diffraction patterns. Meth. Enz. 277, 448–467 (1997).

    Article  CAS  Google Scholar 

  39. Helliwell, J. R. et al. The recording and analysis of synchrotron X-radiation Laue diffraction photographs. J. Appl. Crystallogr. 22, 483–497 (1989).

    Article  CAS  Google Scholar 

  40. Ren, Z., Ng, K., Borgstahl, G. E. O., Getzoff, E. D. & Moffat, K. Quantitative analysis of time-resolved Laue diffraction patterns. J. Appl. Crystallogr. 29 , 246–260 (1996).

    Article  CAS  Google Scholar 

  41. Brünger, A. X-PLOR version 3.1: a system for X-ray crystallography and NMR (Yale Universuty Press, New Haven, Connecticut; 1992).

    Google Scholar 

  42. Brünger, A. Asessment of phase accuracy by cross validation: the free R value. Methods and applications. Acta Crystallogr. D 49, 24–36 (1993).

    Article  Google Scholar 

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Acknowledgements

We thank W. Scott, J. Bolduc, D. Dyer, M. Holmes, R. Strong, and K. Zhang for advice and help with X-ray crystallography, R.M. Sweet, P. Singer, and G. Shea for assistance and technical support at NSLS Beamline X-26C (Brookhaven National Laboratories), D. Ringe and G. Petsko for extended use of their Xe flashlamp, and K. Moffat for extremely helpful advice and criticism at all stages of our time-resolved studies. B.L.S. is funded for this project by the NIH, DEK by the NSF and DOE.

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Stoddard, B., Cohen, B., Brubaker, M. et al. Millisecond Laue structures of an enzyme–product complex using photocaged substrate analogs. Nat Struct Mol Biol 5, 891–897 (1998). https://doi.org/10.1038/2331

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