Structure—activity relations of amiloride derivatives, acting as antagonists of cation binding on Na+/K+-ATPase

David, P.; Mayan, Haim; Cragoe, Edward J.; Karlish, Steven J. D.

doi:10.1016/0005-2736(93)90338-z

Cited by 13 publications

(6 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The data in Table I on competition between the isothiouronium derivatives and Na ϩ or K ϩ (Rb ϩ ) ions allow one to conclude that the highest binding affinity is achieved with compounds having the greatest number of alkyl isothiouronium residues per molecule, three Ͼ two Ͼ one residue, the greatest number of Br atoms in the ring, two Ͼ one Ͼ no Br atoms, while N-substituted methyl derivatives are much less potent. These features are consistent with predictions based on structureactivity relations of the guanidinium derivatives and amiloride analogues (David et al, 1992;David et al, 1993). The increase occlusion by isothiouronium derivatives Na/K-ATPase (25 g) was incubated in 50 l of reaction medium containing 100 mM choline chloride, 10 mM Tris-HCl, pH 8.0, and 50 M…”

Section: Structure-activity Relations Of Isothiouronium Derivatives-supporting

confidence: 87%

See 1 more Smart Citation

Novel Aromatic Isothiouronium Derivatives Which Act as High Affinity Competitive Antagonists of Alkali Metal Cations on Na/K-ATPase

Hoving

Bar-Shimon

Tijmes

et al. 1995

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

This paper describes properties of a novel family of aromatic isothiouronium derivatives, which act as Na(+)-like competitive antagonists on renal Na/K-ATPase. The derivatives are reversible competitors of Rb+ and Na+ occlusion. Ki values of the most potent compounds, 1-bromo-2,4,6-tris(methylisothiouronium)benzene (Br-TITU) and 1,3-dibromo-2,4,6-tris(methylisothiouronium)benzene(Br2-TITU ), 0.65 and 0.32 microM, respectively, are 15-30-fold lower than Ki values of the bis-guanidinium derivatives described previously (David, P., Mayan, H., Cohen, H., Tal, D. M., and Karlish, S. J. D. (1992) J. Biol. Chem. 267, 1141-1149), and represent the lowest reported values for cation antagonists. Using fluorescein-labeled Na/K-ATPase, all derivatives have been shown to stabilize the E1 conformation when bound at high affinity sites (i.e. they are sodium-like). In addition, in one condition (10 mM Tris-HCl, pH 8.1), high concentrations of Br-TITU (KD approximately 10 microM) appear to stabilize an E2 conformation. We propose a model which allows for simultaneous binding of the antagonists to high affinity cytoplasmic sites and low affinity sites, which may be at the extracellular surface. Blockage of cation occlusion by the isothiouronium derivatives at the cytoplasmic surface probably occurs at the entrance to the occlusion sites, which is recognized both by Na+ antagonists and by Na+ or K+ ions. Unlike the alkali metal cations, the Na+ antagonists are not occluded or transported (see also Or, E., David, P., Shainskaya, A., Tal, D. M., and Karlish, S. J. D. (1993) J. Biol. Chem. 268, 16929-16937). The isothiouronium derivatives appear to be promising candidates for further development as affinity labels of cation binding domains, for kinetic analysis of isoforms or mutated Na/K pumps, or as probes of other cation transport proteins.

show abstract

Section: Structure-activity Relations Of Isothiouronium Derivatives-supporting

confidence: 87%

“…Systematic structure-activity studies on the guanidinium derivatives (David et al, 1992) and amiloride analogues (David et al, 1993) led to a number of provisional conclusions concerning expected properties of a putative high affinity Na ϩ antagonist. These conclusions form the basis for a search and design of a new set of compounds of higher affinity.…”

mentioning

confidence: 99%

Novel Aromatic Isothiouronium Derivatives Which Act as High Affinity Competitive Antagonists of Alkali Metal Cations on Na/K-ATPase

Hoving

Bar-Shimon

Tijmes

et al. 1995

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…These data provide additional support for E protein being the likely in vivo target of these compounds, and they suggest that inhibition of the ion channel activity may suppress virus replication. Notably, the activity of EIPA and HMA for the Na+/K+ ATPase is higher than of amiloride [ 66 ]. Therefore, structure-based optimization of target-selectivity will be necessary in order to develop an amiloride-based drug aimed at E protein.…”

Section: Discussionmentioning

confidence: 99%

Interactions of SARS-CoV-2 envelope protein with amilorides correlate with antiviral activity

et al. 2021

View full text Add to dashboard Cite

SARS-CoV-2 is the novel coronavirus that is the causative agent of COVID-19, a sometimes-lethal respiratory infection responsible for a world-wide pandemic. The envelope (E) protein, one of four structural proteins encoded in the viral genome, is a 75-residue integral membrane protein whose transmembrane domain exhibits ion channel activity and whose cytoplasmic domain participates in protein-protein interactions. These activities contribute to several aspects of the viral replication-cycle, including virion assembly, budding, release, and pathogenesis. Here, we describe the structure and dynamics of full-length SARS-CoV-2 E protein in hexadecylphosphocholine micelles by NMR spectroscopy. We also characterized its interactions with four putative ion channel inhibitors. The chemical shift index and dipolar wave plots establish that E protein consists of a long transmembrane helix (residues 8–43) and a short cytoplasmic helix (residues 53–60) connected by a complex linker that exhibits some internal mobility. The conformations of the N-terminal transmembrane domain and the C-terminal cytoplasmic domain are unaffected by truncation from the intact protein. The chemical shift perturbations of E protein spectra induced by the addition of the inhibitors demonstrate that the N-terminal region (residues 6–18) is the principal binding site. The binding affinity of the inhibitors to E protein in micelles correlates with their antiviral potency in Vero E6 cells: HMA ≈ EIPA > DMA >> Amiloride, suggesting that bulky hydrophobic groups in the 5’ position of the amiloride pyrazine ring play essential roles in binding to E protein and in antiviral activity. An N15A mutation increased the production of virus-like particles, induced significant chemical shift changes from residues in the inhibitor binding site, and abolished HMA binding, suggesting that Asn15 plays a key role in maintaining the protein conformation near the binding site. These studies provide the foundation for complete structure determination of E protein and for structure-based drug discovery targeting this protein.

show abstract

“…Amiloride could also inhibit the Na + -K + ATPase [6], Na + -K + -electrochemical gradients [29], and the reaction between acetylcholinesterase and butyrylcholinesterase with their specific choline ester substrates [27]. All of these channel effects could, at least partially, contribute to the reported antinociception of amiloride.…”

Section: Discussionmentioning

confidence: 87%

Antinociceptive effect of intrathecal amiloride on neuropathic pain in rats

Wang

Ouyang

et al. 2015

Neuroscience Letters

View full text Add to dashboard Cite

Structure—activity relations of amiloride derivatives, acting as antagonists of cation binding on Na+/K+-ATPase

Cited by 13 publications

References 19 publications

Novel Aromatic Isothiouronium Derivatives Which Act as High Affinity Competitive Antagonists of Alkali Metal Cations on Na/K-ATPase

Novel Aromatic Isothiouronium Derivatives Which Act as High Affinity Competitive Antagonists of Alkali Metal Cations on Na/K-ATPase

Interactions of SARS-CoV-2 envelope protein with amilorides correlate with antiviral activity

Antinociceptive effect of intrathecal amiloride on neuropathic pain in rats

Contact Info

Product

Resources

About