Elsevier

Ultramicroscopy

Volume 140, May 2014, Pages 32-36
Ultramicroscopy

Single molecule binding dynamics measured with atomic force microscopy

https://doi.org/10.1016/j.ultramic.2014.02.005Get rights and content
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Highlights

  • We discuss the importance of studying single molecule binding rates for surface bound proteins.

  • We show measurements of single molecule binding rates on a model system using AFM.

  • We discuss the influence of various components on the measured binding rates.

Abstract

We present a new method to analyse simultaneous Topography and RECognition Atomic Force Microscopy data such that it becomes possible to measure single molecule binding rates of surface bound proteins. We have validated this method on a model system comprising a S-layer surface modified with Strep-tagII for binding sites and strep-tactin bound to an Atomic Force Microscope tip through a flexible Poly-Ethylene-Glycol linker. At larger distances, the binding rate is limited by the linker, which limits the diffusion of the strep-tactin molecule, but at lateral distances below 3 nm, the binding rate is solely determined by the intrinsic molecular characteristics and the surface geometry and chemistry of the system. In this regime, Kon as determined from single molecule TREC data is in agreement with Kon determined using traditional biochemical methods.

Keywords

Single molecule
Binding kinetics
AFM
Simultaneous Topography and RECognition Imaging
Interaction

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