Paramagnetic relaxation enhancement for the characterization of the conformational heterogeneity in two-domain proteins

Phys Chem Chem Phys. 2012 Jul 7;14(25):9149-56. doi: 10.1039/c2cp40139h. Epub 2012 May 24.

Abstract

Multidomain proteins are often composed of rigid domains that can reorient in solution more or less freely. Calmodulin (CaM) is a two domain protein which can experience a large degree of conformational freedom thanks to a mobile linker connecting the N-terminal and C-terminal domains of the protein. The maximum occurrences (MOs) of the possible protein conformations have been analyzed using the paramagnetic relaxation enhancements (PREs) induced by a gadolinium(III) ion together with the paramagnetic pseudocontact shift and residual dipolar coupling restraints measured in the presence of terbium(III), thulium(III) or dysprosium(III) ions. The results suggest that the PREs provide complementary information useful for improving the description of the conformational heterogeneity of the protein. The data, acquired at 298 K and at 278 K, suggest that compact conformations are disfavoured by decreasing the temperature.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Calmodulin / chemistry*
  • Gadolinium / chemistry
  • Lanthanoid Series Elements / chemistry
  • Models, Molecular
  • Nuclear Magnetic Resonance, Biomolecular / methods*
  • Protein Conformation
  • Protein Structure, Tertiary
  • Temperature

Substances

  • Calmodulin
  • Lanthanoid Series Elements
  • Gadolinium