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Hydropathic interaction analyses of small organic activators binding to antithrombin
Gunnar T Gunnarsson1, Umesh R Desai
1Department of Medicinal Chemistry, Virginia Commonwealth University, 410N. 12th Street, PO Box 980540, Richmond, VA 23298, USA.
Bioorganic & Medicinal Chemistry
|January 24, 2004
Summary
Small organic molecules activate antithrombin to inhibit factor Xa. Computerized analysis reveals these ligands bind well to antithrombin, aiding in the design of new anticoagulants.
Area of Science:
- Biochemistry
- Medicinal Chemistry
- Computational Chemistry
Background:
- Small organic ligands, including sulfated flavonoids, were developed as activators of antithrombin.
- These activators accelerate the inhibition of factor Xa, a critical enzyme in the coagulation cascade.
- Understanding the molecular interactions of these ligands with antithrombin is crucial for drug design.
Purpose of the Study:
- To investigate the binding properties of sulfated flavonoids and flavanoids with antithrombin at a molecular level.
- To utilize hydropathic interaction (HINT) analyses to predict the binding interactions of these ligands with native and activated antithrombin.
- To correlate computational binding predictions with experimental solution data.
Main Methods:
- Computerized hydropathic interaction (HINT) analyses were performed.
- HINT analyses modeled the interactions of sulfated ligands within the pentasaccharide- and extended heparin-binding sites of antithrombin.
- Both native and activated forms of antithrombin were analyzed.
Main Results:
- HINT analyses predicted favorable multi-point interactions for the activators in both binding sites of antithrombin.
- Most activators showed better predicted interaction with activated antithrombin compared to the native form, aligning with experimental observations.
- Specific stereoisomers, (+)-catechin sulfate and (-)-catechin sulfate, exhibited distinct binding preferences for native versus activated antithrombin.
- A linear correlation was observed between HINT scores and the experimental free energy of binding.
Conclusions:
- HINT analysis is a valuable tool for understanding the molecular interactions between antithrombin and small sulfated organic ligands.
- HINT possesses predictive capabilities that can aid in the rational design of new antithrombin activators.
- The study provides molecular insights into why certain ligands function as effective antithrombin activators.