scholarly journals Dependence on Membrane Lipids of the Effect of Vanadate on Calcium and ATP Binding to Sarcoplasmic Reticulum ATPase

1984 ◽  
Vol 39 (11-12) ◽  
pp. 1137-1140 ◽  
Author(s):  
Pankaj Medda ◽  
Wilhelm Hasselbach
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Binding Sites ◽  
Calcium Binding ◽  
Membrane Lipids ◽  
Nucleotide Binding ◽  
Atp Binding ◽  
Transport Atpase ◽  
Nucleotide Binding Sites ◽  
High Affinity ◽  
Calcium Binding Sites

Abstract The affinity of the sarcoplasmic reticulum transport ATPase for calcium and ATP is not affected by lipid depriviation while vanadate binding is completely abolished. Lipid substitution restores vanadate binding as well as the vanadate induced disappearance of the enzyme’s high affinity calcium and nucleotide binding sites. Nucleotide binding is simultaneously restored with the displacement of vanadate from the enzyme following the occupation of its low affinity calcium binding sites.

Low Affinity Calcium Binding Sites of the Calcium Transport ATPase of Sarcoplasmic Reticulum Membranes

1980 ◽  
Vol 35 (11-12) ◽  
pp. 1012-1018 ◽  
Author(s):  
Wilhelm Hasselbach ◽  
Vera Koenig
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Binding Sites ◽  
Calcium Binding ◽  
Calcium Transport ◽  
External Surface ◽  
Transport Atpase ◽  
Affinity Constants ◽  
Calcium Binding Sites ◽  
Short Time

Calcium binding sites having low affinity constants of < 103 ᴍ-1 were titrated in native sarcoplasmic reticulum vesicles as well as in lipid deprived membranes and in the isolated calcium transport ATPase. Short time calcium binding measurements and the determination of the calcium binding heat allow to distinguish low affinity calcium binding sites located on the external surface of the sarcoplasmic reticulum membranes from those present in the section of the transport molecule directed to the vesicular space. The same number of internal binding sites was found for preparations deprived of their lipid content as well as of preparations depleted of their lipids and of their accessorial proteins. Magnesium interferes with calcium binding to the external as well as to the internal low affinity calcium binding sites. The implications of the existence of the low affinity calcium binding sites in the internal section of the calcium transport ATPase are discussed.

A Conformational Transition of the Sarcoplasmic Reticulum Calcium Transport ATPase Induced by Vanadate

1983 ◽  
Vol 38 (11-12) ◽  
pp. 1015-1022 ◽  
Author(s):  
Wilhelm Hasselbach ◽  
Pankaj Medda ◽  
Andrea Migala ◽  
Bruno Agostini
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Binding Sites ◽  
Calcium Binding ◽  
Calcium Transport ◽  
Conformational Transition ◽  
Transport Atpase ◽  
Calcium Binding Sites ◽  
Protein Particles ◽  
Sarcoplasmic Reticulum Calcium ◽  
Internal Calcium

Vanadate binding to sarcoplasmic reticulum vesicles results in the loss of the externally located high affinity calcium binding sites of the calcium transport ATPase. Conversely the occupation by calcium of the internally located low affinity sites in the vanadate enzyme complex leads to the release of vanadate. Since the total number of calcium binding sites is not diminished by vanadate binding but slightly increases we conclude that vanadate binding induces a transition of the enzymes external high to internal low affinity calcium binding sites. The transposition of external to internal calcium binding sites is accompanied by a definite change in the structure of the sarcoplasmic reticulum membranes. On vanadate binding the asymmetrically arranged electron dense protein particles become symmetrically distributed

scholarly journals Mutation of the high affinity calcium binding sites in cardiac troponin C.

1992 ◽  
Vol 267 (2) ◽  
pp. 825-831 ◽  
Author(s):  
J C Negele ◽  
D G Dotson ◽  
W Liu ◽  
H L Sweeney ◽  
J A Putkey
Keyword(s):  
Binding Sites ◽  
Calcium Binding ◽  
Cardiac Troponin ◽  
Troponin C ◽  
High Affinity ◽  
Cardiac Troponin C ◽  
Calcium Binding Sites

Rat GTP cyclohydrolase I is a homodecameric protein complex containing high-affinity calcium-binding sites 1 1Edited by W. Baumeister

1998 ◽  
Vol 279 (1) ◽  
pp. 189-199 ◽  
Author(s):  
Michel O Steinmetz ◽  
Christoph Plüss ◽  
Urs Christen ◽  
Bettina Wolpensinger ◽  
Ariel Lustig ◽  
...  
Keyword(s):  
Protein Complex ◽  
Binding Sites ◽  
Calcium Binding ◽  
Gtp Cyclohydrolase I ◽  
Gtp Cyclohydrolase ◽  
High Affinity ◽  
Calcium Binding Sites

scholarly journals Binding of Calcium to Fibrinogen: Some Related Properties

1977 ◽  
Author(s):  
G. Marguerie
Keyword(s):  
Binding Sites ◽  
Calcium Binding ◽  
Specific Binding ◽  
Equilibrium Dialysis ◽  
Structural Features ◽  
Salt Bridges ◽  
High Affinity ◽  
Direct Titration ◽  
Specific Binding Sites ◽  
Calcium Binding Sites

The calcium binding properties of bovin fibrinogen have been studied using equilibrium dialysis method. At pH 7.5 fibrinogen has 3 specific calcium binding sites of high affinity and several non specific binding sites of low affinity. Direct titration of the calcium induced proton release indicates that the binding center is a chelate. Thermal an acid denaturation is found to be markedly influenced by the presence of Ca++, suggesting that structural features are related to the binding. However the circular dichroism spectra show that no generalized conformational change is induced when Ca++ is bound to the protein.The plasminic digestion of fibrinogen is also found to be specificaly influenced by Ca++. The velocity of the initial cleavages is slightly reduced in the presence of calcium. It is therefore suggested that the C-terminal part of the Aα chain is involved in the binding.Considering the dimeric structure of the fibrinogen molecule, the presence of only 3 calcium binding sites of high affinity suggests the existence of “salt bridges” between the constitutive polypeptide chains.

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