Structural basis for E1–E2 conformational transitions in Na, K-pump and Ca-pump proteins

@article{Jrgensen2005StructuralBF,
  title={Structural basis for E1–E2 conformational transitions in Na, K-pump and Ca-pump proteins},
  author={P. L. J{\o}rgensen and J. Andersen},
  journal={The Journal of Membrane Biology},
  year={2005},
  volume={103},
  pages={95-120}
}
The primary active transport of Na +, K +, Ca 2T and H + in eukaryotic cells is driven by ATP-powered cation pumps, the Na,K pump, Ca pump and H,K pump. The intermediary steps of the pump reactions and their relationship to cation translocation have been examined in detail, particularly for the Na,K-pump and Ca-pump proteins. A common feature of these pumps is a protein of Mr close to 110,000 that binds ATP and accepts its y-phosphate in a covalent Asp-P bond. There is evidence that both… Expand
Structure and mechanism of Na,K-ATPase: functional sites and their interactions.
TLDR
Evidence is related on functional sites of Na,K-ATPase for the substrate (ATP), the essential cofactor (Mg(2+) ions), and the transported cations (Na(+) and K(+)) to the molecular structure to address the central questions of mechanism of active cation transport by all P-type cation pumps. Expand
Specific Sites in the Cytoplasmic N Terminus Modulate Conformational Transitions of the Na,K-ATPase*
TLDR
Observations suggest that sites 31KKE in H1 and 47HRK in H2 have distinct roles in modulating the enzyme's conformational transitions during the catalytic cycle of the Na,K-ATPase. Expand
Transmission of E1‐E2 Structural Changes in Response to Na+ or K+ Binding in Na,K‐ATPase
  • P. L. Jørgensen
  • Chemistry, Medicine
  • Annals of the New York Academy of Sciences
  • 2003
TLDR
The model of the E2 form provides a remarkable fit to the data of direct Tl+ or K+ binding after site‐directed mutagenesis of residues Asp804 and Asp808 in M6, Glu 779, Gln776, and Ser775 in M5, and Glu327 in M4. Expand
Identification of a Potential Receptor That Couples Ion Transport to Protein Kinase Activity*
TLDR
The data suggest that the Src-coupled α1 Na/K-ATPase may act as a Na+/K+ receptor, allowing salt to regulate cellular function through Src and Src effectors. Expand
Electrostatic Stabilization Plays a Central Role in Autoinhibitory Regulation of the Na+,K+-ATPase.
TLDR
Electrostatic stabilization of the Na+,K+-ATPase's E2 conformation could play an important role in regulating the enzyme's physiological catalytic turnover, as indicated by eosin fluorescence and stopped-flow kinetic data. Expand
Interaction of ATP with the phosphoenzyme of the Na+,K+-ATPase.
TLDR
Investigation of the interaction of ATP with the phosphoenzyme of Na(+),K(+)-ATPase from pig kidney, rabbit kidney, and shark rectal gland and stopped-flow studies on the shark enzyme indicated that the ATP-induced inhibition of dephosphorylation is abolished in the presence of 1 mM KCl. Expand
The fourth extracellular loop of the alpha subunit of Na,K-ATPase. Functional evidence for close proximity with the second extracellular loop.
TLDR
An extensive conformational space search is performed using simulated annealing and it is shown that the Tyr(308) and Asp(884) residues can be in close proximity, and simultaneously, the SYGQ motif of the fourth extracellular loop can be exposed to the exterior of the protein and can easily interact with the beta subunit. Expand
Regulation of Membrane Na+-K+ ATPase in Health and Disease
Na+-K+ ATPase is primarily localized in the plasma membrane and occurs in the form of α-subunits (α-1, -2, and -3 isoforms) and β-subunits (β-1 and -2 isoforms) mainly. The inhibition of this enzymeExpand
Charge translocation by the Na,K-pump: I. Kinetics of local field changes studied by time-resolved fluorescence measurements
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Evidence is presented that the styryl dye mainly responds to changes of the electric field strength in the membrane, resulting from charge movements during the pumping cycle, and electrochromic dyes can be used for studying electrogenic processes in microsomal membrane preparations which are not amenable to electrophysiological techniques. Expand
Dual mechanisms of allosteric acceleration of the Na(+),K(+)-ATPase by ATP.
TLDR
It is indicated that ATP has two separate mechanisms whereby it accelerates the E2 --> E1 transition of Na(+),K(+)-ATPase alphabeta protomers and (alphabeta)(2) diprotomers. Expand
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TLDR
In this study, circular dichroism spectroscopy was utilized to assess the secondary structural composition of the enzyme, particularly with regard to the E1 and E2 states that are associated with the presence of Na+ and K+, respectively. Expand
Localization of E1–E2 conformational transitions of sarcoplasmic reticulum Ca-ATPase by tryptic cleavage and hydrophobic labeling
TLDR
Hydrophobic labeling of Ca-ATPase in sarcoplasmic reticulum vesicles with the photoactivable reagent trifluoromethyl-[125I]iodophenyl-diazirine indicated that E2 and E2V states are more exposed to the membrane phase than E1 and E1P (Ca2+-occluded) states. Expand
STRUCTURE OF THE Na, K PUMP: CRYSTALLIZATION OF PURE MEMBRANE‐BOUND Na, K‐ATPase AND IDENTIFICATION OF FUNCTIONAL DOMAINS OF THE α‐SUBUNIT
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Preparation and analysis of two-dimensional crystallization in two dimensions of the proteins in the pure membrane-bound Na.K-ATPase provide information about molecular sizes and subunit structure of the Na,K pump protein. Expand
Electrical potential accelerates the E1P(Na)----E2P conformational transition of (Na,K)-ATPase in reconstituted vesicles.
TLDR
In experiments with fluorescein-labeled (Na,K)-ATPase, the use of acetyl phosphate rather than ATP, which does not bind, provides a valuable tool to detect fluorescence signals accompanying steps in the turnover cycle. Expand
The active site structure of Na+/K+-transporting ATPase: location of the 5'-(p-fluorosulfonyl)benzoyladenosine binding site and soluble peptides released by trypsin.
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  • Chemistry, Medicine
  • Proceedings of the National Academy of Sciences of the United States of America
  • 1986
TLDR
To establish any regions of the enzyme protruding from the membrane, the native Na+/K+-transporting ATPase from the electric ray, Torpedo californica, was treated with trypsin; and four peptides, which were released into the water phase, were purified and sequenced. Expand
Yeast plasma membrane ATPase is essential for growth and has homology with (Na+ + K+), K+- and Ca2+-ATPases
TLDR
The strong homology between the ammo-acid sequence encoded by PMA1 and those of (Na+ + K+), Na+-, K+- and Ca2+-ATPases is consistent with the notion that the family of cation pumps which form a phosphorylated intermediate evolved from a common ancestral ATPase. Expand
Affinity modification of E1‐form of Na+, K+ ‐ATPase revealed Asp‐710 in the catalytic site
TLDR
E1‐ and E2‐enzymes have different targets in CIRATP modification, i.e. the polypeptide chain regions near the ATP γ‐phosphate in the enzyme active site differ somewhat in their conformations. Expand
Identification of a membrane-embedded segment of the large polypeptide chain of (Na+, K+)ATPase
THE sodium pump or (Na+, K+)ATPase couples hydrolysis of ATP to the active transport of Na+ and K+ across the cell membrane. The firm association of the enzyme with the membrane allows itsExpand
Two Ca2+ ATPase genes: Homologies and mechanistic implications of deduced amino acid sequences
TLDR
A transport mechanism is proposed in which Ca2+ binds to negatively charged groups on amphipathic stalk sectors, becoming occluded during enzyme phosphorylation by bound ATP. Expand
Conformational transitions between Na+-bound and K+-bound forms of (Na+ + K+)-ATPase, studied with formycin nucleotides.
TLDR
A model for the sodium pump is proposed in which conformational changes alternate with trans-phosphorylations, and the inward and outward fluxes of both Na+ and K+ each involve the transfer of a phosphoryl group as well as a change in conformation between E1 and E2 forms of the enzyme or phosphoenzyme. Expand
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