Probing the topography of the intramembrane part of Na+,K+-ATPase by photolabelling with 3-(trifluoromethyl)-3_(m[125I]iodophenyl)diazirine Analysis of the hydrophobic domain of the β-subunit

E. N. Chertova, S. V. Lutsenko, N. B. Levina, N. N. Modyanov

Research output: Contribution to journalArticlepeer-review


The mutual disposition of the α-helical intramembrane rods in Na+,K+-ATPase subunits was studied by photolabelling of the membrane-bound enzyme with 3-(trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine ([125I]TID). Under the chosen conditions for modification, the ratio of label incorporated into the subunits was found to be α/β = 2.2, demonstrating the peripheral location of the β-subunit in the oligomeric membrane complex. The [125I]TID-labelled β-subunit was subjected to tryptic hydrolysis and the modified fragment (Thr27-Arg71) was isolated. The labelled amino acid residues are located predominantly on one side of the helix, which is helpful in unravelling the spatial orientation of the β-subunit relative to the α-subunit.

Original languageEnglish (US)
Pages (from-to)13-16
Number of pages4
JournalFEBS Letters
Issue number1-2
StatePublished - Aug 28 1989
Externally publishedYes


  • ATPase, Na,K-
  • Hydrophobic photolabeling
  • Trifluoromethyliodophenyldiazirine

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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