Interaction Force Fluctuations in Antigen−Antibody Biorecognition Studied by Atomic Force Spectroscopy
Author(s)
Attila Gergely Végh, György Váró, and Salvatore Cannistraro
Date Issued
2019
Type
article
Journal
Abstract
The formation of a specific complex between
β2μglobulin and antiβ2μglobulin was investigated by analyzing
the force fluctuations recorded in an atomic force spectroscopy
biorecognition experiment. We found that a 1/f noise
appears in the power spectra of force fluctuations when the tip,
functionalized with β2μglobulin, reaches a distance of 0.50 nm
from the partner-charged substrate while a specific biorecognition process occurs. Concomitantly, in this active region, the
distribution of the times spent by the tip in the proximity of the substrate exhibits a power law trend characterized by a longtime
tail. All of these findings are put into relationship to a slowing down of the energy landscape exploration, consistent with a
restricted sampling dynamics of the conformational states driving to the final binding state. The hypothesis that a combination
of a conformational substrate and an induced fit hybrid binding mechanism controls the specific complex formation is put
forward and discussed also in connection with the fluctuations of the hydration water network.