Restrained-ensemble molecular dynamics simulations based on distance histograms from double electron-electron resonance spectroscopy

J Phys Chem B. 2013 May 2;117(17):4733-9. doi: 10.1021/jp3110369. Epub 2013 Apr 11.

Abstract

DEER (double electron-electron resonance) spectroscopy is a powerful pulsed ESR (electron spin resonance) technique allowing the determination of spin-spin distance histograms between site-directed nitroxide label sites on a protein in their native environment. However, incorporating ESR/DEER data in structural refinement is challenging because the information from the large number of distance histograms is complex and highly coupled. Here, a novel restrained-ensemble molecular dynamics simulation method is developed to incorporate the information from multiple ESR/DEER distance histograms simultaneously. Illustrative tests on three coupled spin-labels inserted in T4 lysozyme show that the method efficiently imposes the experimental distance distribution in this system. Different rotameric states of the χ1 and χ2 dihedrals in the spin-labels are also explored by restrained ensemble simulations. Using this method, it is hoped that experimental restraints from ESR/DEER experiments can be used to refine structural properties of biological systems.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Bacteriophage T4 / enzymology
  • Cyclic N-Oxides / chemistry
  • Electron Spin Resonance Spectroscopy
  • Electrons
  • Mesylates / chemistry
  • Molecular Dynamics Simulation*
  • Muramidase / chemistry*
  • Muramidase / metabolism
  • Spin Labels

Substances

  • Cyclic N-Oxides
  • Mesylates
  • Spin Labels
  • (1-oxyl-2,2,5,5-tetramethylpyrroline-3-methyl)methanethiosulfonate
  • Muramidase