Thermodynamics of mixing of phosphatidylserine/phosphatidylcholine from measurements of high-affinity calcium binding

Biochemistry ◽  
1990 ◽  
Vol 29 (36) ◽  
pp. 8291-8297 ◽  
Author(s):  
Joy E. Swanson ◽  
Gerald W. Feigenson
Keyword(s):  
Calcium Binding ◽  
High Affinity ◽  
Thermodynamics Of Mixing

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.

HIGH AFFINITY CALCIUM BINDING TO DOMAINES OF PROTEIN C THAT ARE HOMOLOGUS TO THE EPIDERMAL GROWTH FACTOR

1987 ◽  
Author(s):  
A KÖhlin ◽  
J Stenflo
Keyword(s):  
Calcium Ions ◽  
Calcium Ion ◽  
Calcium Binding ◽  
Plasma Proteins ◽  
Metal Ion ◽  
Protein C ◽  
Protein S ◽  
Protein Z ◽  
High Affinity ◽  
Epidermal Growth

In addition to γ-carboxyglutamic acid (Gla)-dependent calcium binding all of the vitamin K-dependent plasma proteins, except prothrombin, have one or two high affinity calcium binding sites that do not require the Gla residues. A common denominator among these proteins (factors IX, X, protein C, protein Z and protein S) is that they have domaines that are homologus to the epidermal growth factor (EGF) precursor. In factors VII,IX,X, protein C and in protein Z the aminoterminal of two EGF homology regions contain one residue of β-hydroxyaspartic acid (Hya) whereas in protein S the aminoterminal EGF homology region contains Hya and the three following contain one β-hydroxyasparagine residue each.In an attempt to elucidate the role of the EGF homology regions in the Gla independent calcium binding we have isolated a tryptic fragment (residue 44-138) from the light chain of human protein C. The fragment was isolated using a monoclonal antibody that recognizes a calcium ion stabilized epitope that is expressed both in intact protein C and in protein C lacking the Gla domaine.The antibody bound the isolated EGF homology region in the presence of calcium ions but not in EDTA containing buffer. A calcium ion titration showed half maximal binding at approximately 200 μM Ca2+. The metal ion induced conformational change in the isolated fragment was also studied with affinity purified rabbit antibodies against Gla domainless protein C. Antibodies that bound in the presence of calcium ions and that could be eluted with EDTA recognized the metal ion induced conformational change in the isolated EGF homology domain. Our results suggest that one or both of the EGF homology regions are involved in the Gla-independent high affinity calcium binding in the vitamin K-dependent plasma proteins.

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