Crossref journal-article
Proceedings of the National Academy of Sciences
Proceedings of the National Academy of Sciences (341)
Abstract

Hydrogen atoms play a central role in many biochemical processes yet are difficult to visualize by x-ray crystallography. Spallation neutron sources provide a new arena for protein crystallography with TOF measurements enhancing data collection efficiency and allowing hydrogen atoms to be located in smaller crystals of larger biological macromolecules. Here we report a 2.2-Å resolution neutron structure of Escherichia coli dihydrofolate reductase (DHFR) in complex with methotrexate (MTX). Neutron data were collected on a 0.3-mm 3 D 2 O-soaked crystal at the Los Alamos Neutron Scattering Center. This study provides an example of using spallation neutrons to study protein dynamics, to identify protonation states directly from nuclear density maps, and to analyze solvent structure. Our structure reveals that the occluded loop conformation [monomer (mon.) A] of the DHFR·MTX complex undergoes greater H/D exchange compared with the closed-loop conformer (mon. B), partly because the Met-20 and β(F-G) loops readily exchange in mon. A. The eight-stranded β sheet of both DHFR molecules resists H/D exchange more than the helices and loops. However, the C-terminal strand, βH, in mon. A is almost fully exchanged. Several D 2 Os form hydrogen bonds with exchanged amides. At the active site, the N1 atom of MTX is protonated and thus charged when bound to DHFR. Several D 2 Os are observed at hydrophobic surfaces, including two pockets near the MTX-binding site. A previously unidentified D 2 O hydrogen bonds with the catalytic D27 in mon. B, stabilizing its negative charge.

Bibliography

Bennett, B., Langan, P., Coates, L., Mustyakimov, M., Schoenborn, B., Howell, E. E., & Dealwis, C. (2006). Neutron diffraction studies of Escherichia coli dihydrofolate reductase complexed with methotrexate. Proceedings of the National Academy of Sciences, 103(49), 18493–18498.

Authors 7
  1. Brad Bennett (first)
  2. Paul Langan (additional)
  3. Leighton Coates (additional)
  4. Marat Mustyakimov (additional)
  5. Benno Schoenborn (additional)
  6. Elizabeth E. Howell (additional)
  7. Chris Dealwis (additional)
References 53 Referenced 52
  1. 10.1038/288414a0
  2. 10.1073/pnas.80.12.3628
  3. 10.1021/bi010626h
  4. 10.1038/nsb1197-909
  5. 10.1073/pnas.0403807101
  6. 10.1107/S0909049503023859
  7. 10.1073/pnas.0405109101
  8. 10.1038/224143a0
  9. 10.1107/S0909049503023902
  10. 10.1107/S0907444905004804
  11. 10.1021/bi010621k
  12. 10.1021/bi00048a011
  13. 10.1073/pnas.052005999
  14. 10.1002/tcr.10009
  15. 10.1146/annurev.biophys.33.110502.133613
  16. 10.1021/bi962337c
  17. 10.1021/bi048119y
  18. 10.1073/pnas.0500699102
  19. 10.1073/pnas.172501499
  20. 10.1016/S0021-9258(18)33497-5
  21. 10.1021/bi051378i
  22. 10.1021/bi00008a039
  23. 10.1016/S0959-440X(98)80018-3
  24. 10.1016/S0958-1669(98)80088-8
  25. 10.1021/bi971337p
  26. 10.1006/jmbi.1995.0397
  27. 10.1038/296713a0
  28. 10.1093/jb/mvh080
  29. 10.1016/j.jmb.2005.11.084
  30. 10.1016/0022-2836(73)90011-9
  31. 10.1021/bi00064a036
  32. 10.1021/bi00413a033
  33. 10.1016/S0021-9258(18)48363-9
  34. 10.1016/S0969-2126(99)80097-5
  35. 10.1093/bioinformatics/19.2.313
  36. 10.1016/j.tibs.2003.09.004
  37. 10.1002/prot.20219
  38. I Khavrutskii, D Price, J Lee, CL Brooks The American Chemical Society Meeting and Exposition (Am Chem Soc, Atlanta, 2006). / The American Chemical Society Meeting and Exposition by Khavrutskii I (2006)
  39. 10.1021/bi00259a006
  40. 10.1021/bi00222a028
  41. 10.1016/S0006-3495(86)83536-6
  42. 10.1107/S0907444998018514
  43. 10.1021/bi00110a011
  44. W Gu, AE Garcia, BP Schoenborn Basic Life Sci 64, 289–298 (1996). / Basic Life Sci by Gu W (1996)
  45. 10.1016/0167-4838(83)90056-0
  46. 10.1021/bi00517a005
  47. 10.1016/0003-9861(83)90326-0
  48. 10.1021/bi00370a069
  49. 10.1016/0014-5793(92)80923-5
  50. 10.1021/bi00009a018
  51. 10.1021/bi990301p
  52. 10.1006/jmbi.1997.1173
  53. G Sheldrick, T Schneider Methods in Enzymology, eds CW Carter, RM Sweet (Academic, San Diego) Vol 277 (1997). / Methods in Enzymology by Sheldrick G (1997)
Dates
Type When
Created 18 years, 9 months ago (Nov. 27, 2006, 10:41 p.m.)
Deposited 3 years, 4 months ago (April 12, 2022, 3:18 p.m.)
Indexed 1 year, 2 months ago (June 3, 2024, 8:34 p.m.)
Issued 18 years, 8 months ago (Dec. 5, 2006)
Published 18 years, 8 months ago (Dec. 5, 2006)
Published Online 18 years, 8 months ago (Dec. 5, 2006)
Published Print 18 years, 8 months ago (Dec. 5, 2006)
Funders 0

None

@article{Bennett_2006, title={Neutron diffraction studies of Escherichia coli dihydrofolate reductase complexed with methotrexate}, volume={103}, ISSN={1091-6490}, url={http://dx.doi.org/10.1073/pnas.0604977103}, DOI={10.1073/pnas.0604977103}, number={49}, journal={Proceedings of the National Academy of Sciences}, publisher={Proceedings of the National Academy of Sciences}, author={Bennett, Brad and Langan, Paul and Coates, Leighton and Mustyakimov, Marat and Schoenborn, Benno and Howell, Elizabeth E. and Dealwis, Chris}, year={2006}, month=dec, pages={18493–18498} }