Naslov
Labeling of a cysteine in the cardiotonic glycoside binding site by the steroid derivative HDMA

Autori
Antolović, Roberto ; Schoner, Wilhelm ; Geering, Kathi ; Canessa, Cecilia ; Rossier, Bernard C. ; Horisberger J.D.

Izvornik
FEBS letters (0014-5793) 368 (1995), 1; 169-172

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Na ; K-ATPase ; cardiac steroid ; xenopus laevis oocyte ; site-directed mutagenesis ; affinity labeling

Sažetak
The digoxigenin derivative N-hydroxysuccinimidyl digoxigenin-3-O-methylcarbonyl-epsilon- aminocaproate (HDMA) has been shown to covalently label the ouabain binding site of the Na, K-ATPase epsilon subunit [Antolovic et al. (1995) Eur. J. Biochem. 227, 61-67]. In the present study we observed both, labeling and inactivation of the activity, of wild type Na, K-ATPase overexpressed in Xenopus oocyte. In contrast, no significant inhibition and no labeling could be detected when a Cys-113 of the first transmembrane segment was mutated to serine, although the affinity of this mutant for digoxigenin or HDMA measured in acute inhibition experiments was similar to the wild type. This indicates that after docking of its genin moiety, HDMA can form a thioester bond with Cys-113.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA