Na,K‐ATPase labelled with 5‐iodoacetamidofluorescein: E2‐E1 conformational transition induced by different nucleotides

FEBS Letters

Pindel, E.V.¹  Lopina, O.D.¹  Boldyrev, A.A.¹ 

[1] Department of Biochemistry, School of Biology, Moscow State University, Moscow 119899, USSR

关键词: Na;    K-ATPase;    5-Iodoacetamidofluorescein;    Conformational transition;    ATP binding site;    IAF;    5-iodoacetamidofluorescein;    IAF-enzyme;    Na;    K-ATPase labelled with IAF;   

DOI  :  10.1016/0014-5793(90)81510-U

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A conformational transition between E₂ and E₁ forms of Na, K-ATPase induced by different nucleotides has been studied under steady state conditions using the enzyme labelled with 5-iodoacetamidofluorescein. In the presence of K⁺ the plot of fluorescence as a function of [ATP], [ADP] or [CTP] (in a range of 5 μM-12 mM) is a biphasic one. A similar dependence for AMP, ITP, GTP and UTP demonstrates a hyperbolic behaviour. The data suggest that the shift in the equilibrium between E₂ and E₁ forms of Na,K-ATPase towards the E₁ conformation is induced by ATP binding both with high and low affinity sites. Two structural features of ATP are apparently important for its interaction with more than one type of ATP binding sites or for providing for E₂-E₁ transition induced by this interaction: (i) β-phosphate group in the terminal part of the molecule, (ii) unprotonated N₁ and/or NH₂-group in the 6th position of the purine base.

【 授权许可】

Unknown