Cooperative calcium binding and ATPase activation in sarcoplasmic reticulum vesicles.

Inesi, Giuseppe; Kurzmack, M.; Coan, Carol; Lewis, David E.

doi:10.1016/s0021-9258(19)85846-5

Cited by 382 publications

(112 citation statements)

References 41 publications

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“…SERCAs are members of a family of membrane bound ion-motive P-type ATPases, which are characterized by the obligatory formation of a high energy phosphorylated intermediate as part of their catalytic cycle. The active transport of calcium ions from cytosol to sarcoplasmic or endoplasmic reticulum is brought about by SERCA at a stoichiometry of two calcium ions translocated for each ATP hydrolyzed (Inesi et al, 1980). A spectrum of missense, nonse nse, frameshift, and splicing mutations in ATP2A2 has been described in at least 100 families with DD (Jacobsen et al, 1999;Ruiz-Perez et al, 1999;Sakuntabhai et al, 1999a;1999b;2000;Ringpfeil et al, 2001;Takahashi et al, 2001;Yang et al, 2001).…”

mentioning

confidence: 99%

Acrokeratosis Verruciformis of Hopf is Caused by Mutation in ATP2A2: Evidence That it is Allelic to Darier's Disease

Dhitavat¹,

Macfarlane²,

Dode³

et al. 2003

Journal of Investigative Dermatology

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Acrokeratosis verruciformis of Hopf is a localized disorder of keratinization affecting the distal extremities. Onset is early in life and the disease is inherited in an autosomal dominant fashion. Although histology of acrokeratosis verruciformis lesions shows no evidence of dyskeratosis, a possible relationship with Darier's disease has long been postulated on the basis of clinical similarity. ATP2A2 encoding the sarco(endo)plasmic reticulum Ca2+ ATPase2 pump has been identified as the defective gene in Darier's disease. In this report, we studied a family affected with acrokeratosis verruciformis in six generations and identified a heterozygous P602L mutation in ATP2A2. This mutation predicts a nonconservative amino acid substitution in the ATP binding domain of the molecule. The mutation segregates with the disease phenotype in the family and was not found in 50 controls. Moreover, functional analysis of the P602L mutant showed that it has lost its ability to transport Ca2+. This result demonstrates loss of function of the sarco(endo)plasmic reticulum Ca2+ ATPase2 mutant in acrokeratosis verruciformis, thus providing evidence that acrokeratosis verruciformis and Darier's disease are allelic disorders.

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mentioning

confidence: 99%

Acrokeratosis Verruciformis of Hopf is Caused by Mutation in ATP2A2: Evidence That it is Allelic to Darier's Disease

Dhitavat¹,

Macfarlane²,

Dode³

et al. 2003

Journal of Investigative Dermatology

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“…6 in Henderson et al, 1994). Somewhat lower values of K 1/2 at pH 6.8-7.4 were reported by Inesi et al (1980) (0.5 mM) and by Peinelt and Apell (2002) (0.59 mM); moreover, in both cases a Hill coefficient close to 2 was reported, thus suggesting a strong cooperativity in the binding of the two Ca 21 ions. The discrepancy between the above high cooperativity and the apparently slight cooperativity found herein can be possibly explained if the binding of the second Ca 21 ion to be bound or the release of the second Ca 21 ion to be released do not reach full equilibrium conditions during the presteady-state measurements in this study.…”

Section: Ca 21 Concentration Jumps In the Absence Of Atpmentioning

confidence: 61%

“…In fact, a high cooperativity implies that the binding of the second Ca 21 ion to be bound, or the release of the second Ca 21 ion to be released, is favored with respect to the case that the two binding sites are occupied independently. In this respect it should be noted that strong evidence exists that the binding of the second Ca 21 ion is preceded by a conformational change induced by the binding of the first Ca 21 ion (Inesi et al, 1980;Henderson et al, 1994), according to the following mechanism:…”

Section: Ca 21 Concentration Jumps In the Absence Of Atpmentioning

confidence: 99%

“…Henderson et al (1994) regard this transition as in quasi-equilibrium, with an equilibrium constant of unity, on the basis of the belief that tryptophan fluorescence intensity is unlikely to be equally sensitive to the occupancy of the two different binding sites by Ca 21 ions. On the other hand, Inesi et al (1980) consider the conformational transition as a slow step (see also Dupont and Leigh, 1978), appreciably shifted toward the E 1 Ca form, on the basis of equilibrium binding data combined with electron paramagnetic resonance spectroscopic measurements on spinlabeled preparations sensitive to conformational changes. Some evidence for cooperativity in the binding of the two Ca 21 ions is provided by the time dependence of the offcurrent after Ca 21 concentration jumps in the absence of ATP.…”

Section: Ca 21 Concentration Jumps In the Absence Of Atpmentioning

confidence: 99%

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Time-Resolved Charge Translocation by Sarcoplasmic Reticulum Ca-ATPase Measured on a Solid Supported Membrane

Tadini‐Buoninsegni

Bartolommei

Moncelli

et al. 2004

Biophysical Journal

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Sarcoplasmic reticulum vesicles were adsorbed on an octadecanethiol/phosphatidylcholine mixed bilayer anchored to a gold electrode, and the Ca-ATPase contained in the vesicles was activated by ATP concentration jumps both in the absence and in the presence of K(+) ions and at different pH values. Ca(2+) concentration jumps in the absence of ATP were also carried out. The resulting capacitive current transients were analyzed together with the charge under the transients. The relaxation time constants of the current transients were interpreted on the basis of an equivalent circuit. The current transient after ATP concentration jumps and the charge after Ca(2+) concentration jumps in the absence of ATP exhibit almost the same dependence upon the Ca(2+) concentration, with a half-saturating value of approximately 1.5 microM. The pH dependence of the charge after Ca(2+) translocation demonstrates the occurrence of one H(+) per one Ca(2+) countertransport at pH 7 by direct charge-transfer measurements. The presence of K(+) decreases the magnitude of the current transients without altering their shape; this decrease is explained by K(+) binding to the cytoplasmic side of the pump in the E(1) conformation and being released to the same side during the E(1)-E(2) transition.

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“…For example, the formation of an acyl phosphate from inorganic phosphate and a carboxylate group at the active site of the calcium ATPase of sarcoplasmic reticulum in the absence of calcium occurs readily, with an equilibrium constant close to 1.0 at pH 7.0 (Hasselbach 1974;de Meis & Vianna 1979;Inesi et al 1980;Pickart & Jencks 1984). The formation of an acyl phosphate in solution is extremely unfavourable with AG0' = 10.3 kcal mol-1 for 1 m reactants at pH 7.0 (de Meis & Vianna 1979;Jencks 1983).…”

Section: (B) Coupling Of Binding Energiesmentioning

confidence: 99%

Destabilization is as important as binding

1993

Phil. Trans. R. Soc. Lond. A

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Enzymes make use of non-covalent interactions with their substrates to bring about a large fraction of their catalytic activity. These interactions must destabilize, or increase the Gibbs energy, of the substrate in the active site in order that the transition state can be reached easily. This destabilization may be brought about by utilization of the intrinsic binding energy between the active site and the bound substrate by desolvation of charged groups, geometric distortion, electrostatic interactions and, especially, loss of entropy in the enzyme-substrate complex. These mechanisms are described by interaction energies and require utilization of the intrinsic binding energy that is realized from non-covalent interactions between the enzyme and substrate. Receptors and coupled vectorial processes, such as muscle contraction and active transport, utilize binding energy similarly to avoid large peaks and valleys along the Gibbs energy profile of the reaction under physiological conditions.

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Cooperative calcium binding and ATPase activation in sarcoplasmic reticulum vesicles.

Cited by 382 publications

References 41 publications

Acrokeratosis Verruciformis of Hopf is Caused by Mutation in ATP2A2: Evidence That it is Allelic to Darier's Disease

Acrokeratosis Verruciformis of Hopf is Caused by Mutation in ATP2A2: Evidence That it is Allelic to Darier's Disease

Time-Resolved Charge Translocation by Sarcoplasmic Reticulum Ca-ATPase Measured on a Solid Supported Membrane

Destabilization is as important as binding

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