Structure-function relationships of Na+, K+, ATP, or Mg2+ binding and energy transduction in Na,K-ATPase
Publikation: Bidrag til tidsskrift › Review › Forskning › fagfællebedømt
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Structure-function relationships of Na+, K+, ATP, or Mg2+ binding and energy transduction in Na,K-ATPase. / Jorgensen, Peter L.; Pedersen, Per A.
I: Biochimica et Biophysica Acta - Bioenergetics, Bind 1505, Nr. 1, 01.05.2001, s. 57-74.Publikation: Bidrag til tidsskrift › Review › Forskning › fagfællebedømt
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TY - JOUR
T1 - Structure-function relationships of Na+, K+, ATP, or Mg2+ binding and energy transduction in Na,K-ATPase
AU - Jorgensen, Peter L.
AU - Pedersen, Per A.
PY - 2001/5/1
Y1 - 2001/5/1
N2 - The focus of this article is on progress in establishing structure-function relationships through site-directed mutagenesis and direct binding assay of Tl+, Rb+, K+, Na+, Mg2+ or free ATP at equilibrium in Na,K-ATPase. Direct binding may identify residues coordinating cations in the E2[2K] or E1P[3Na] forms of the ping-pong reaction sequence and allow estimates of their contributions to the change of Gibbs free energy of binding. This is required to understand the molecular basis for the pronounced Na/K selectivity at the cytoplasmic and extracellular surfaces. Intramembrane Glu327 in transmembrane segment M4, Glu779 in M5, Asp804 and Asp808 in M6 are essential for tight binding of K+ and Na+. Asn324 and Glu327 in M4, Thr774, Asn776, and Glu779 in 771-YTLTSNIPEITP of M5 contribute to Na+/K+ selectivity. Free ATP binding identifies Arg544 as essential for high affinity binding of ATP or ADP. In the 708-TGDGVND segment, mutations of Asp710 or Asn713 do not interfere with free ATP binding. Asp710 is essential and Asn713 is important for coordination of Mg2+ in the E1P[3Na] complex, but they do not contribute to Mg2+ binding in the E2P-ouabain complex. Transition to the E2P form involves a shift of Mg2+ coordination away from Asp710 and Asn713 and the two residues become more important for hydrolysis of the acyl phosphate bond at Asp369.
AB - The focus of this article is on progress in establishing structure-function relationships through site-directed mutagenesis and direct binding assay of Tl+, Rb+, K+, Na+, Mg2+ or free ATP at equilibrium in Na,K-ATPase. Direct binding may identify residues coordinating cations in the E2[2K] or E1P[3Na] forms of the ping-pong reaction sequence and allow estimates of their contributions to the change of Gibbs free energy of binding. This is required to understand the molecular basis for the pronounced Na/K selectivity at the cytoplasmic and extracellular surfaces. Intramembrane Glu327 in transmembrane segment M4, Glu779 in M5, Asp804 and Asp808 in M6 are essential for tight binding of K+ and Na+. Asn324 and Glu327 in M4, Thr774, Asn776, and Glu779 in 771-YTLTSNIPEITP of M5 contribute to Na+/K+ selectivity. Free ATP binding identifies Arg544 as essential for high affinity binding of ATP or ADP. In the 708-TGDGVND segment, mutations of Asp710 or Asn713 do not interfere with free ATP binding. Asp710 is essential and Asn713 is important for coordination of Mg2+ in the E1P[3Na] complex, but they do not contribute to Mg2+ binding in the E2P-ouabain complex. Transition to the E2P form involves a shift of Mg2+ coordination away from Asp710 and Asn713 and the two residues become more important for hydrolysis of the acyl phosphate bond at Asp369.
KW - ATP binding
KW - Cation binding site
KW - Energy transduction
KW - K binding
KW - Mg binding
KW - Mutagenesis
KW - Na,K-ATPase
KW - Na binding
KW - Tl binding
UR - http://www.scopus.com/inward/record.url?scp=0035342633&partnerID=8YFLogxK
U2 - 10.1016/S0005-2728(00)00277-2
DO - 10.1016/S0005-2728(00)00277-2
M3 - Review
C2 - 11248189
AN - SCOPUS:0035342633
VL - 1505
SP - 57
EP - 74
JO - B B A - Bioenergetics
JF - B B A - Bioenergetics
SN - 0005-2728
IS - 1
ER -
ID: 227039505