Interaction of N-terminal peptide analogues of the Na+,K+-ATPase with membranes

Khoa Nguyen, Alvaro Garcia, Marc Antoine Sani, Dil Diaz, Vikas Dubey, Daniel Clayton, Giovanni Dal Poggetto, Flemming Cornelius, Richard J. Payne, Frances Separovic, Himanshu Khandelia, Ronald J. Clarke*

*Corresponding author for this work

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The Na+,K+-ATPase, which is present in the plasma membrane of all animal cells, plays a crucial role in maintaining the Na+ and K+ electrochemical potential gradients across the membrane. Recent studies have suggested that the N-terminus of the protein's catalytic α-subunit is involved in an electrostatic interaction with the surrounding membrane, which controls the protein's conformational equilibrium. However, because the N-terminus could not yet be resolved in any X-ray crystal structures, little information about this interaction is so far available. In measurements utilising poly-L-lysine as a model of the protein's lysine-rich N-terminus and using lipid vesicles of defined composition, here we have identified the most likely origin of the interaction as one between positively charged lysine residues of the N-terminus and negatively charged headgroups of phospholipids (notably phosphatidylserine) in the surrounding membrane. Furthermore, to isolate which segments of the N-terminus could be involved in membrane binding, we chemically synthesized N-terminal fragments of various lengths. Based on a combination of results from RH421 UV/visible absorbance measurements and solid-state 31P and 2H NMR using these N-terminal fragments as well as MD simulations it appears that the membrane interaction arises from lysine residues prior to the conserved LKKE motif of the N-terminus. The MD simulations indicate that the strength of the interaction varies significantly between different enzyme conformations.

Original languageEnglish
JournalBBA Biomembranes
Issue number6
Pages (from-to)1282-1291
Publication statusPublished - 2018


  • Eosin
  • Lipid-protein interaction
  • Molecular dynamics simulations
  • Phosphatidylserine
  • Phospholipid membrane
  • Poly‑L‑lysine


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