The DFPase from Loligo vulgaris in sugar surfactant-based bicontinuous microemulsions: structure, dynamics, and enzyme activity

Abstract

The enzyme diisopropyl fluorophosphatase (DFPase) from the squid Loligo vulgaris is of great interest because of its ability to catalyze the hydrolysis of highly toxic organophosphates. In this work, the enzyme structure in solution (native state) was studied by use of different scattering methods. The results are compared with those from hydrodynamic model calculations based on the DFPase crystal structure. Bicontinuous microemulsions made of sugar surfactants are discussed as host systems for the DFPase. The microemulsion remains stable in the presence of the enzyme, which is shown by means of scattering experiments. Moreover, activity assays reveal that the DFPase still has high activity in this complex reaction medium. To complement the scattering experiments cryo-SEM was also employed to study the microemulsion structure.

Acceleration of membrane dynamics adjacent to a wall

“…The possible treatment of diffusion as an additive term was discussed by Hellweg and coworkers [39,40]. The relative amplitudes must favor the undulations at high Q.…”

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“…Contrary, in SANS and NSE measurements on the enzyme DFPase incorporated into the aqueous phase of a sugar surfactant-based microemulsion, there was no different behavior of the two bare bending elasticities. This spherically shaped enzyme shows no amphiphilicity and remains in the aqueous phase (Wellert et al, 2011). In conclusion, the results presented in the present paper in light of the previous phase studies allow for the following interpretation.…”

“…Beside the influence of composition and thermodynamic variables, the changes in the phase structures due to the presence of additives, for example, enzymes, are accessible by applying these techniques, which improves the understanding of the bio-organic reaction mechanisms inside microemulsions (Hayes et al, 2015). For example, a combination of scattering techniques was used to investigate the effect of the enzyme DFPase, which efficiently hydrolyzes organophosphates, on the structure and dynamics of the host microemulsion with a bicontinuous structure (Wellert et al, 2011). Moreover, enzymes, such as the green fluorescent protein can be used as probes inside the aqueous phase of bicontinuous microemulsions to study fundamentals of diffusion in confinement (Wrede et al, 2019).…”

Bicontinuous Interfacially Jammed Emulsion Gels (bijels) as Media for Enabling Enzymatic Reactive Separation of a Highly Water Insoluble Substrate

“…However, slow mass transfer due to the limited interfacial area between two immiscible liquid phases significantly limits efficient conversion 8–10 . Although the interfacial area could be increased by energy-intensive emulsification, the addition of surfactants 11 , or the use of sponge phases 12,13 and microemulsions 14–16 , these approaches may not be favored because enzymes can be undesirably deactivated by shear stress 17–19 or surfactants, resulting in inefficient conversion 20–22 . Surfactants at the interface also form barriers to interphase mass transfer, reducing the efficacy of the enzymatic process.…”