Eight amino acids form the ATP recognition site of Na(+)/K(+)-ATPase.
Point mutations of a part of the H(4)-H(5) loop (Leu(354)-Ile(604)) of Na(+)/K(+)-ATPase have been used to study the ATP and TNP-ATP binding affinities. Besides the previously reported amino acid residues Lys(480), Lys(501), Gly(502), and Cys(549), we have found four more amino acid residues, viz., Glu(446), Phe(475), Gln(482), and Phe(548), completing the ATP-binding pocket of Na(+)/K(+)-ATPase. Moreover, mutation of Arg(423) has also resulted in a large decrease in the extent of ATP binding. This residue, localized outside the binding pocket, seems to play a key role in supporting the proper structure and shape of the binding site, probably due to formation of a hydrogen bond with Glu(472). On the other hand, only some minor effects were caused by mutations of Ile(417), Asn(422), Ser(445), and Glu(505).
Kubala
Martin
M
Institute of Physiology, Academy of Sciences of the Czech Republic, Vídenská 1083, 14220 Prague, Czech Republic.
Teisinger
Jan
J
Ettrich
Rüdiger
R
Hofbauerová
Katerina
K
Kopecký
Vladimír
V
Baumruk
Vladimír
V
Krumscheid
Rita
R
Plásek
Jaromír
J
Schoner
Wilhelm
W
Amler
Evzen
E
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000596:Amino Acids / Q000737:chemistry*; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000201:enzymology; D003545:Cysteine / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D005816:Genetic Complementation Test; D005822:Genetic Vectors; D018698:Glutamic Acid / Q000737:chemistry; D005973:Glutamine / Q000737:chemistry; D006860:Hydrogen Bonding; D051379:Mice; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D010649:Phenylalanine / Q000737:chemistry; D017354:Point Mutation; D011485:Protein Binding; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D017550:Spectroscopy, Fourier Transform Infrared
D000596:Amino Acids; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D005973:Glutamine; D018698:Glutamic Acid; D010649:Phenylalanine; D000255:Adenosine Triphosphate; D000254:Sodium-Potassium-Exchanging ATPase; D003545:Cysteine