Cysteine‐scanning mutagenesis study of the sixth transmembrane segment of the Na,K‐ATPase α subunit

FEBS Letters

Horisberger, Jean-Daniel¹  Guennoun, Saı̈da¹ 

[1] Institute of Pharmacology and Toxicology, Bugnon 27, CH-1005 Lausanne, Switzerland

关键词: Na;    K-ATPase;    Palytoxin;    Cysteine scanning;    Cation binding site;    Structure–function relationship;   

DOI  :  10.1016/S0014-5793(02)02323-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The accessibility of the residues of the sixth transmembrane segment (TM) of the Bufo marinus Na,K-ATPase α subunit was explored by cysteine scanning mutagenesis. Methanethiosulfonate reagents reached only the two most extracellular positions (T803, D804) in the native conformation of the Na,K-pump. Palytoxin induced a conductance in all mutants, including D811C, T814C and D815C which showed no active electrogenic transport. After palytoxin treatment, four additional positions (V805, L808, D811 and M816) became accessible to the sulfhydryl reagent. We conclude that one side of the sixth TM helix forms a wall of the palytoxin-induced channel pore and, probably, of the cation pathway from the extracellular side to one of their binding sites.

【 授权许可】

Unknown