What question did this study set out to answer?

To investigate how membrane phospholipid composition influences the binding affinity, capacity, and stoichiometry of the coagulation proteins prothrombin and factor X.

September 1, 1977Biochemistry

Interaction of prothrombin and blood-clotting factor X with membranes of varying composition

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To investigate how membrane phospholipid composition influences the binding affinity, capacity, and stoichiometry of the coagulation proteins prothrombin and factor X.
Assessed prothrombin and factor X binding interactions across lipid membranes prepared with varying ratios of acidic and neutral phospholipids, including phosphatidylserine, phosphatidic acid, phosphatidylethanolamine, and phosphatidylglycerol.
Quantified maximum protein binding capacity, stoichiometry (residues per protein molecule), and dissociation constants across distinct lipid concentrations.
Protein binding strictly required acidic phospholipids, with maximum binding capacity scaling proportionally with phosphatidylserine content up to ~15% at a stoichiometry of 9.2 ± 1.3 residues per prothrombin and 5.2 ± 1.5 residues per factor X molecule.
Above ~20% phosphatidylserine, binding was constrained by protein packing density, reaching a maximum binding capacity of 1.2 g protein per gram of phospholipid at 50% phosphatidylserine.
Phosphatidic acid mediated binding with higher dissociation constants than phosphatidylserine, whereas adding small quantities of phosphatidylserine to poorly binding lipids (phosphatidylethanolamine and phosphatidylglycerol) substantially increased membrane-binding affinity.

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Implication

In vitro study demonstrates that acidic phospholipids regulate prothrombin and factor X membrane binding, indicating that phosphatidylserine concentration and clustering drive coagulation assembly.

Cite This Study

Nelsestuen et al. (1977) studied this question.

synapsesocial.com/papers/6a1c8b7094dbf6307b2fe675 https://doi.org/10.1021/bi00638a006

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Implication

In vitro study demonstrates that acidic phospholipids regulate prothrombin and factor X membrane binding, indicating that phosphatidylserine concentration and clustering drive coagulation assembly.

Interaction of prothrombin and blood-clotting factor X with membranes of varying composition

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Discussion

Implication

Cite This Study

Interaction of prothrombin and blood-clotting factor X with membranes of varying composition

Key Points

Discussion

Implication

Cite This Study

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