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

FEBS Letters

Chertova, E.N.¹  Levina, N.B.¹  Modyanov, N.N.¹  Lutsenko, S.V.¹ 

[1] Shemyakin Institute of Bioorganic Chemistry, USSR Academy of Sciences, Moscow, USSR

关键词: ATPase;    Na+;    K+-;    Hydrophobic photolabeling;    Trifluoromethyliodophenyldiazirine;   

DOI  :  10.1016/0014-5793(89)80999-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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.

【 授权许可】

Unknown