Analysis of side chain rotational restrictions of membrane-embedded proteins by spin-label ESR spectroscopy

J Magn Reson. 2009 Apr;197(2):245-8. doi: 10.1016/j.jmr.2008.12.019. Epub 2008 Dec 24.

Abstract

Site-directed spin-labeling electron spin resonance (SDSL-ESR) is a promising tool for membrane protein structure determination. Here we propose a novel way to translate the local structural constraints gained by SDSL-ESR data into a low-resolution structure of a protein by simulating the restrictions of the local conformational spaces of the spin label attached at different protein sites along the primary structure of the membrane-embedded protein. We test the sensitivity of this approach for membrane-embedded M13 major coat protein decorated with a limited number of strategically placed spin labels employing high-throughput site-directed mutagenesis. We find a reasonably good agreement of the simulated and the experimental data taking a protein conformation close to the one determined by fluorescence resonance energy transfer analysis [P.V. Nazarov, R.B.M. Koehorst, W.L. Vos, V.V. Apanasovich, M.A. Hemminga, FRET study of membrane proteins: determination of the tilt and orientation of the N-terminal domain of M13 major coat protein, Biophys. J. 92 (2007) 1296-1305].

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Capsid Proteins / chemistry
  • Electron Spin Resonance Spectroscopy / methods*
  • Lipids / chemistry
  • Membrane Proteins / chemistry*
  • Models, Molecular
  • Protein Conformation
  • Spin Labels*

Substances

  • Capsid Proteins
  • Lipids
  • Membrane Proteins
  • Spin Labels