Spatial distribution and activity of Na ⁺/K ⁺-ATPase in lipid bilayer membranes with phase boundaries

TY - JOUR

T1 - Spatial distribution and activity of Na +/K +-ATPase in lipid bilayer membranes with phase boundaries

AU - Bhatia, Tripta

AU - Cornelius, Flemming

AU - Brewer, Jonathan

AU - Bagatolli, Luis A.

AU - Simonsen, Adam C.

AU - Ipsen, John H.

AU - Mouritsen, Ole G.

PY - 2016/6/1

Y1 - 2016/6/1

N2 - We have reconstituted functional Na +/K +-ATPase (NKA) into giant unilamellar vesicles (GUVs) of well-defined binary and ternary lipid composition including cholesterol. The activity of the membrane system can be turned on and off by ATP. The hydrolytic activity of NKA is found to depend on membrane phase, and the water relaxation in the membrane on the presence of NKA. By collapsing and fixating the GUVs onto a solid support and using high-resolution atomic-force microscopy (AFM) imaging we determine the protein orientation and spatial distribution at the single-molecule level and find that NKA is preferentially located at l o/l d interfaces in two-phase GUVs and homogeneously distributed in single-phase GUVs. When turned active, the membrane is found to unbind from the support suggesting that the protein function leads to softening of the membrane.

AB - We have reconstituted functional Na +/K +-ATPase (NKA) into giant unilamellar vesicles (GUVs) of well-defined binary and ternary lipid composition including cholesterol. The activity of the membrane system can be turned on and off by ATP. The hydrolytic activity of NKA is found to depend on membrane phase, and the water relaxation in the membrane on the presence of NKA. By collapsing and fixating the GUVs onto a solid support and using high-resolution atomic-force microscopy (AFM) imaging we determine the protein orientation and spatial distribution at the single-molecule level and find that NKA is preferentially located at l o/l d interfaces in two-phase GUVs and homogeneously distributed in single-phase GUVs. When turned active, the membrane is found to unbind from the support suggesting that the protein function leads to softening of the membrane.

KW - Domains

KW - Giant unilamellar vesicles

KW - Membrane biophysics

KW - Membrane protein

KW - Membranes

KW - Na /K -ATPase

KW - Protein-lipid interaction

UR - http://www.scopus.com/inward/record.url?scp=84962476173&partnerID=8YFLogxK

U2 - 10.1016/j.bbamem.2016.03.015

DO - 10.1016/j.bbamem.2016.03.015

M3 - Journal article

C2 - 26994932

AN - SCOPUS:84962476173

SN - 0005-2736

VL - 1858

SP - 1390

EP - 1399

JO - B B A - Biomembranes

JF - B B A - Biomembranes

IS - 6

ER -