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Theoretical Modeling of Hydrophobin Adsorption Kinetics at the Air-Water Interface
##manager.scheduler.building##: Edificio Santa Maria
##manager.scheduler.room##: Auditorio San Agustin
Date: 2019-07-10 12:00 PM – 03:45 PM
Last modified: 2019-06-14
Abstract
Hydrophobins are surface-active proteins which are known to adsorb to an air-water interface and form 2D crystalline films. In this study, we consider the adsorption kinetics for class II hydrophobins both experimentally and theoretically. Experimentally, the kinetics were measured by monitoring the accumulated mass at the interface via non-destructive ellipsometry measurements. The measured mass vs. time for wild-type HFBI and HFBII exhibited linear adsorption kinetics at the air-water interface before the adsorbed amount reaching the saturation value, while adsorption kinetics for their engineered variants showed time-dependent kinetics. The underlying mechanism of these behaviors has not been known yet. Theoretically, we have modeled the formation of the films of HFBI and HFBII at the air-water interfaces. We introduce a stochastic model which includes microscopic movements of proteins in the air-water interface and in the solution as well as interactions between proteins. In our model, proteins are accumulated in the interface via two-step adsorption, i) pre-adsorption, in which proteins adsorb from the solution to the reservoir and ii) final adsorption from reservoir to the interface. We showed that the kinetics of the system is dominated by two factors: the diffusive motion in the reservoir and the adsorption rate from the reservoir to the interface. Our stochastic model captures the observed behavior of both wild-type HFBI and HFBII.