Taxonomic distribution of proteins containing Cation_ATPase_N domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing Cation_ATPase_N domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Structure determination and conformational change induced by tyrosinephosphorylation of the N-terminal domain of the alpha-chain of pig gastricH+/K+-ATPase.

Fujitani N, Kanagawa M, Aizawa T, Ohkubo T, Kaya S, Demura M, Kawano K, Nishimura S, Taniguchi K, Nitta K
Biochem Biophys Res Commun. 2003; 300: 223-9

It has been well established that phosphorylation is an important reactionfor the regulation of protein functions. In the N-terminal domain of thealpha-chain of pig gastric H(+)/K(+)-ATPase, reversible sequentialphosphorylation occurs at Tyr 10 and Tyr 7. In this study, we determinedthe structure of the peptide involving the residues from Gly 2 to Gly 34of pig gastric H(+)/K(+)-ATPase and investigated the tyrosinephosphorylation-induced conformational change using CD and NMRexperiments. The solution structure showed that the N-terminal fragmenthas a helical conformation, and the peptide adopted two alpha-helices in50% trifluoroethanol (TFE) solvent, suggesting that the peptide has a highhelical propensity under hydrophobic conditions. Furthermore, the CD andNMR data suggested that the structure of the N-terminal fragment becomesmore disordered as a result of phosphorylation of Tyr 10. Thisconformational change induced by the phosphorylation of Tyr 10 might be anadvantageous reaction for sequential phosphorylation and may be importantfor regulating the function of H(+)/K(+)-ATPase.

Structural basis for alpha1 versus alpha2 isoform-distinct behavior of theNa,K-ATPase.

Segall L, Javaid ZZ, Carl SL, Lane LK, Blostein R
J Biol Chem. 2003; 278: 9027-34

We showed earlier that the kinetic behavior of the alpha2 isoform of theNa,K-ATPase differs from the ubiquitous alpha1 isoform primarily by ashift in the steady-state E(1)/E(2) equilibrium of alpha2 in favor of E(1)form(s). The aim of the present study was to identify regions of the alphachain that confer the alpha1/alpha2 distinct behavior using a mutagenesisand chimera approach. Criteria to assess shifts in conformationalequilibrium included (i) K(+) sensitivity of Na-ATPase measured atmicromolar ATP, under which condition E(2)(K(+)) --> E(1) + K(+) becomesrate-limiting, (ii) changes in K'(ATP) for low affinity ATP binding, (iii)vanadate sensitivity of Na,K-ATPase activity, and (iv) the rate of thepartial reaction E(1)P --> E(2)P. We first confirmed that interactionsbetween the cytoplasmic domains of alpha2 that modulate conformationalshifts are fundamentally similar to those of alpha1, suggesting that thepredilection of alpha2 for E(1) state(s) is due to differences in primarystructure of the two isoforms. Kinetic behavior of the alpha1/alpha2chimeras indicates that the difference in E(1)/E(2) poise of the twoisoforms cannot be accounted for by their notably distinct N termini, butrather by the front segment extending from the cytoplasmic N terminus tothe C-terminal end of the extracellular loop between transmembranes 3 and4, with a lesser contribution of the alpha1/alpha2 divergent portionwithin the M4-M5 loop near the ATP binding domain. In addition, we showthat the E(1) shift of alpha2 results primarily from differences in theconformational transition of the dephosphoenzyme, (E(2)(K(+)) --> E(1) +K(+)), rather than phosphoenzyme (E(1)P --> E(2)P).