Application of three-dimensional molecular hydrophobicity potential to the analysis of spatial organization of membrane domains in proteins. III. Modeling of intramembrane moiety of Na+, K(+)-ATPase.
The most probable interlocation of transmembrane alpha-helices of Na+, K(+)-ATPase has been calculated by a computer-aided molecular simulation approach in the framework of models with eight and 10 helical peptides for the alpha-subunit. The method is based on the concept of three-dimensional molecular hydrophobicity potential (MHP) and provides valuable description of spatial hydrophobic properties of membrane-spanning segments as well as helix-helix packing interactions inside the membrane. Resulting model of the arrangement of intramembrane domain agrees with recent results on hydrophobic photolabeling of an intramembrane part of the beta-subunit and the sixth transmembrane segment of the alpha-subunit. It is also consistent with current ideas on hydrophobic organization of integral membrane proteins. Possible topology of a cation-binding site is discussed.
Efremov
R G
RG
Shemyakin Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow.
Gulyaev
D I
DI
Modyanov
N N
NN
D002462:Cell Membrane / Q000201:enzymology; D003198:Computer Simulation; D008958:Models, Molecular; D011487:Protein Conformation; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D014867:Water; D000254:Sodium-Potassium-Exchanging ATPase