Mikael Esmann

Solid-state NMR detection of ATP interacting with Na,K-ATPase

Mikael Esmann
Professor, DSc, DMSc
More information  

RESEARCH
Structure-function relationships for Na,K-ATPase is the main area of research. We wish to elucidate the detailed molecular mechanism by which the chemical energy stored in ATP is converted to an energy demanding transport of Na+ and K+ across the plasma cell membrane. Ouabain binding is studied with solid-state NMR methods, and specifically labelled ouabain derivatives are used to map the binding site at room temperature, which will yield dynamic information as a supplement to the static high-resolution crystal structures with bound ouabain. The probable stabilizing effect of ouabain on Na,K-ATPase protein structure is monitored by synchrotron radiation circular dichroism spectroscopy (SRCD), including a comparison of shark and pig Na,K-ATPase . We also apply NMR to study ATP binding to Na,K-ATPase, focusing on the role of Mg2+ in altering the structure of the binding site. The combined binding of Mg2+ and ATP leads to the initial step of the cation translocation, which conceivably involves major rearrangements in the protein structure.  The effect of small peptides of the FXYD-family on Na,K-ATPase activity is studied in order to clarify their potential roles in cell homeostasis and under patophysiological conditions. The last project concerns the structure and dynamics of the lipid bilayer in which the Na,K-ATPase is embedded. The pressure profile of the lipid bilayer is studied using spin-labelled lipids, and conventional as well as pulsed EPR techniques will be employed. The goal of this latter project is to elucidate the role of bilayer dynamics for cation pumping by the Na,K-ATPase .

RESEARCH INTERESTS

Purification and characterization of membrane proteins.

Detergent/protein interactions.

Fluorescence methods for protein/ligand interactions.

Enzyme-kinetic methods for ligand binding to membrane proteins.

Development of suitable protocols for preparation and analysis of membrane proteins using NMR, EPR and CD spectroscopy.

METHODOLOGIES

  • Large scale preparation of Na,K-ATPase from various tissues
  • Rapid filtration methods for determination of ligand binding
  • Rapid kinetic methods

COLLABORATORS & Centers

  • Natalya U. Fedosova, Department of Biomedicine
  • David A. Middleton, Liverpool University, Liverpool, Great Britain
  • Derek Marsh, Max-Planck-Institut  für biophysikalische Chemie, Göttingen, Germany
  • Rosa Bartucci, Department of Physics, University of Calabria, Rende, Italy
  • Bonnie A. Wallace and Andrew Miles, Birkbeck College, University of London, London, Great Britain
  • Niels Christian Nielsen, Department of Chemistry, Science and Technology, Aarhus University
  • Søren Vrønning Hoffmann, Department of Physics, Science and Technology, Aarhus University

Research Group  Members
Angelina Damgaard, technician

Henvendelse om denne sides indhold: 
Revideret 03.08.2016