Adhesion Forces Between Individual Ligand-Receptor Pairs

Abstract

The adhesion force between the tip of an atomic force microscope cantilever derivatized with avidin and agarose beads functionalized with biotin, desthiobiotin, or iminobiotin was measured. Under conditions that allowed only a limited number of molecular pairs to interact, the force required to separate tip and bead was found to be quantized in integer multiples of 160 +/- 20 piconewtons for biotin and 85 +/- 15 piconewtons for iminobiotin. The measured force quanta are interpreted as the unbinding forces of individual molecular pairs.

In situ observation of streptavidin‐biotin binding on an immunoassay well surface using an atomic force microscope

“…Si3N4 probe surface [9]. Before use, probes were rinsed in deionised water to remove loosely bound biological material.…”

“…Lee et al [8] used biotin fuctionalised glass beads attached to AFM cantilevers and streptavidin coated mica surfaces to estimate the strength of a single streptavidin-biotin bond. A similar approach was adopted by Gaub et al [9,10,12,13], who measured quantised forces of interaction between a biotinylated agarose bead and an AFM probe functionalised with avidin, a 67 kDa protein closely related to streptavidin.…”

Liaisons « accrocheuses » et mécanique moléculaire

“…Dès 1994, deux équipes de chercheurs [19,20] observaient la rupture de liaisons moléculaires individuelles au moyen d'une méthode entièrement différente: la microscopie de force atomique. Cette approche puissante repose sur un concept extrêmement simple ( Figure 2C, D): une surface couverte de ligands est approchée d'une pointe extrêmement fine (un rayon de courbure de quelques dizaines de nanomètres) recouverte de récepteurs.…”

“…Le modèle de l'interaction avidine/biotine avait été choisi parce qu'il s'agit de la plus forte interaction non covalente caractérisée en biologie. La force de rupture mesurée était comprise entre 160 pN [19] et 300-400 pN [20]. Ces variations pouvaient-elles s'expliquer par les incertitudes expérimentales ?…”

Mechanical unfolding of a2‐macroglobulin molecules with atomic force microscope

“…To mention only a few examples from many exciting reports, we think (1) the imaging of live cells and living processes as summarized in [2], (2) the growth and division of yeast cells [3], and (3) the polymerization processes of biopolymers [4] have much to offer in terms of the usefulness of AFM in life science. Another very important and exciting application of AFM was demonstrated by Florin et al [5]. Exploiting the measuring capacity of AFM, they reported a force measurement between single molecules of avidin and biotin, a system of wide biochemical use due to their unusually strong interaction.…”