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A trivalent system from vancomycin.D-ala-D-Ala with higher affinity than avidin.biotin
1Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
Science (New York, N.Y.)
|May 23, 1998
Summary
Tris(vancomycin carboxamide) achieves exceptionally high affinity binding to a trivalent ligand, demonstrating a novel approach to creating stable molecular interactions. This research highlights the power of polyvalency in designing potent receptor-ligand systems.
Area of Science:
- Supramolecular Chemistry
- Chemical Biology
Background:
- Designing high-affinity molecular recognition systems is crucial for various applications.
- Polyvalent binding strategies offer a promising avenue for achieving enhanced binding affinities compared to monovalent interactions.
Purpose of the Study:
- To investigate the binding affinity and thermodynamics of a tris(vancomycin carboxamide) system with a trivalent ligand derived from D-Ala-D-Ala.
- To compare the characteristics of trivalent binding with monovalent binding.
Main Methods:
- Isothermal titration calorimetry (ITC) was employed to measure binding thermodynamics.
- High-affinity binding was quantified by determining the dissociation constant (Kd).
Main Results:
- The tris(vancomycin carboxamide) system exhibited an extremely high binding affinity with a dissociation constant (Kd) of approximately 4 x 10(-17) M.
- Calorimetric measurements showed an additive gain in enthalpy, suggesting cooperative binding.
- The study differentiated trivalent binding mechanisms from monovalent binding, noting that trivalent dissociation can be influenced by monovalent ligand concentrations.
Conclusions:
- This system represents one of the most stable small molecule organic receptor-ligand pairs known.
- The findings underscore the effectiveness of polyvalency in designing highly stable and high-affinity molecular recognition systems.