Details

Autor(en) / Beteiligte

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

Titel

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

Ist Teil von

• Biochimica et biophysica acta. Biomembranes, 2018-06, Vol.1860 (6), p.1282-1291

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2018

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• 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.