The formation of a specific complex between β 2 μglobulin and antiβ 2 μglobulin 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 β 2 μglobulin, 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 long-time 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.
ASJC Scopus subject areas
- Chemical Engineering(all)