Role of homologous ASP334 and GLU319 in human non-gastric H,K- and Na,K-ATPases in cardiac glycoside binding.
Biochem Biophys Res Commun
; 356(1): 142-6, 2007 Apr 27.
Article
em En
| MEDLINE
| ID: mdl-17349614
ABSTRACT
Cardiac steroids inhibit Na,K-ATPase and the related non-gastric H,K-ATPase, while they do not interact with gastric H,K-ATPase. Introducing an arginine, the residue present in the gastric H,K-ATPase, in the second extracellular loop at the corresponding position 334 in the human non-gastric H,K-ATPase (D334R mutation) rendered it completely resistant to 2mM ouabain. The corresponding mutation (E319R) in alpha1 Na,K-ATPase produced a approximately 2-fold increase of the ouabain IC(50) in the ouabain-resistant rat alpha1 Na,K-ATPase and a large decrease of the ouabain affinity of human alpha1 Na,K-ATPase, on the other hand this mutation had no effect on the affinity for the aglycone ouabagenin. These results provide a strong support for the orientation of ouabain in its biding site with its sugar moiety interacting directly with the second extracellular loop.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Glicosídeos Cardíacos
/
ATPase Trocadora de Sódio-Potássio
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ATPase Trocadora de Hidrogênio-Potássio
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Substituição de Aminoácidos
Limite:
Animals
/
Female
/
Humans
Idioma:
En
Revista:
Biochem Biophys Res Commun
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Estados Unidos