Amiloride and harmaline are potent inhibitors of NhaB a Na+/H+ antiporter from Escherichia coli

FEBS Letters

Schuldiner, Shimon¹  Pinner, Elhanan¹  Padan, Etana¹ 

[1] Division of Microbial and Molecular Ecology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel

关键词: Transport;    Salinity;    Membrane protein;    Proteoliposome;    Reconstitution;    HTP;    hydroxylapatite;    DTT;    dithiothreitol;    PL;    E. coli phospholipids;    OG;    n-octyl glucoside;    DM;    MOPS;    3-(N-morpholino)propanesulphonic acid;    EIPA;    5-(N-ethyl-N-isopropyl)amiloride;    MIBA;    5-(N-methyl-N-isobutyl)amiloride;    HMA;    5-(N;    N-hexamethylene)amiloride;    DMA;    5-(N;    N-dimethyl)amiloride;   

DOI  :  10.1016/0014-5793(95)00364-F

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The diuretic drug amiloride is a specific inhibitor of sodium transporting proteins in several cell types. Attempts to inhibit this activity in membrane vesicles derived from various bacteria, did not yield clear results. Therefore, we tested the effect of amiloride and its derivatives on the purified Na⁺/H⁺ antiporters of E. coli reconstituted in functional form in proteoliposomes. Whereas NhaA is not inhibited by amiloride, both amiloride and harmaline are potent inhibitors of NhaB with K _0.5 of 6 and 15 μM, respectively. The pattern of inhibition by amiloride derivatives is different from that reported for mammalian antiporters but similar to that reported for the Na⁺/H⁺ antiporter of D. salia [Katz, A., Kleyman, T.R. and Pick, U. (1994) Biochemistry 33, 2389–2393]. Clonidine is a poor inhibitor (K _0.5 = 200 μM) while cimetidine had no effect on the antiporter up to concentration of 1 mM. These new potent inhibitors provide us with important tools for the study of the mechanism of action of NhaB.

【 授权许可】

Unknown