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Analyte gradient-surface plasmon resonance: a one-step method for determining kinetic rates and macromolecular
M L Shank-Retzlaff1, S G Sligar
1Beckman Institute for Advanced Science and Technology, Department of Chemistry, University of Illinois Champaign-Urbana, 61801, USA.
Analytical Chemistry
|September 20, 2000
Summary
A new analyte gradient-surface plasmon resonance (AG-SPR) method enables rapid, accurate determination of binding kinetics and affinities. This technique simplifies analysis, even for complex interactions, by eliminating surface regeneration needs.
Area of Science:
- Biochemistry
- Analytical Chemistry
- Biophysics
Background:
- Surface plasmon resonance (SPR) is a widely used technique for studying molecular interactions.
- Traditional SPR methods can be time-consuming and require surface regeneration.
- Characterizing complex binding kinetics and affinities often presents challenges.
Purpose of the Study:
- To introduce a novel one-step method, analyte gradient-surface plasmon resonance (AG-SPR), for determining kinetic rates and equilibrium binding affinities.
- To demonstrate the accuracy and versatility of AG-SPR through numerical simulations and experimental validation.
- To offer an advantageous alternative to traditional SPR methods by reducing analysis time and eliminating the need for surface regeneration.
Main Methods:
- Development of AG-SPR utilizing a gradient maker or HPLC pump to create a linearly increasing analyte concentration over time.
- Measurement of binding rates by monitoring changes in SPR minimum as analyte concentration increases.
- Kinetic rate determination using a modified two-compartment model and quantitative analysis of experimental data.
Main Results:
- Numerical simulations confirmed AG-SPR's accuracy in estimating kinetic rates and equilibrium affinities, even under mass transport limitations and for heterogeneous receptor populations.
- Experimental application to the interaction of cytochrome c with immobilized cytochrome b5 successfully characterized both specific and nonspecific binding.
- AG-SPR demonstrated significant speed advantages over traditional titration experiments and eliminated the need for surface regeneration.
Conclusions:
- AG-SPR is a robust and efficient method for characterizing molecular interactions, providing accurate kinetic and affinity data.
- The technique is applicable to a wide range of biomolecular systems, including those with complex kinetics.
- AG-SPR offers a faster and more streamlined approach compared to conventional SPR techniques, enhancing experimental throughput.