Journal of Biomolecular NMR

, 51:227

High-resolution membrane protein structure by joint calculations with solid-state NMR and X-ray experimental data

  • Ming Tang
  • Lindsay J. Sperling
  • Deborah A. Berthold
  • Charles D. Schwieters
  • Anna E. Nesbitt
  • Andrew J. Nieuwkoop
  • Robert B. Gennis
  • Chad M. Rienstra
Communication

Abstract

X-ray diffraction and nuclear magnetic resonance spectroscopy (NMR) are the staple methods for revealing atomic structures of proteins. Since crystals of biomolecular assemblies and membrane proteins often diffract weakly and such large systems encroach upon the molecular tumbling limit of solution NMR, new methods are essential to extend structures of such systems to high resolution. Here we present a method that incorporates solid-state NMR restraints alongside of X-ray reflections to the conventional model building and refinement steps of structure calculations. Using the 3.7 Å crystal structure of the integral membrane protein complex DsbB-DsbA as a test case yielded a significantly improved backbone precision of 0.92 Å in the transmembrane region, a 58% enhancement from using X-ray reflections alone. Furthermore, addition of solid-state NMR restraints greatly improved the overall quality of the structure by promoting 22% of DsbB transmembrane residues into the most favored regions of Ramachandran space in comparison to the crystal structure. This method is widely applicable to any protein system where X-ray data are available, and is particularly useful for the study of weakly diffracting crystals.

Keywords

Membrane protein Solid-state NMR X-ray reflections High resolution Joint calculation 

Supplementary material

10858_2011_9565_MOESM1_ESM.pdf (444 kb)
Supplementary material 1 Experimental procedures, 13C-13C correlation spectra of glycerol labeled DsbB samples and validations of structural calculations of DsbB-DsbA. (PDF 443 kb)

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • Ming Tang
    • 1
  • Lindsay J. Sperling
    • 1
  • Deborah A. Berthold
    • 1
  • Charles D. Schwieters
    • 2
  • Anna E. Nesbitt
    • 1
  • Andrew J. Nieuwkoop
    • 1
  • Robert B. Gennis
    • 1
  • Chad M. Rienstra
    • 1
  1. 1.Department of ChemistryUniversity of Illinois at Urbana-ChampaignUrbanaUSA
  2. 2.Division of Computational Bioscience, Center for Information TechnologyNational Institutes of HealthBethesdaUSA

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