Co-assembly of functionally active membrane proteins in mesostructured silica, Brad Chmelka, Department of Chemical Engineering, University of California, Santa Barbara. Thursday June 26 at 2 pm in Amphi Charpak, ESPCI Paris-PSL.
The physicochemical properties of membrane proteins, such as for ion transport, selective catalysis, or biosensing, are desirable for technological applications, although they are challenging to harness in synthetic abiotic host materials. This is due, in part, to the challenges of incorporating relatively fragile protein molecules at sufficient concentrations in robust host environments in which the functionalities of the membrane proteins are retained. Nevertheless, judicious selections of self-assembling surfactants, solvent, silica precursors, and synthesis conditions enable high concentrations of functionally active membrane proteins to be stabilized in robust mesostructured inorganic-surfactant host matrices. Specifically, light-activated proteorhodopsin, a transmembrane protein that pumps H+ ions in green light, has been incorporated at high loadings (>30 wt%) into transparent silica-surfactant films with high extents of mesostructural order. Small-angle X-ray scattering, solid-state NMR, and cryo-EM analyses yield detailed insights on the extent of mesoscale order and the nanoscale interactions of the protein, surfactant, and silica species in the hybrid materials. Transient UV−visible spectroscopy analyses show that the proteorhodopsin molecules exhibit native-like conformational dynamics, as well as enhanced stability compared to surfactant or lipid environments. The results correlate the compositions, structures, dynamics, and properties of the proteorhodopsin molecules in mesostructured silica-surfactant host materials, which have potential applications for solar-to-electrochemical energy conversion.
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C.-T. Han, et al., “Lipid membrane mimetics and oligomerization tune functional properties of proteorhodopsin,” Biophys. J., 122, 1–12 (2023).
J.P. Jahnke, et al., “Mesostructured materials with controllable long-range orientational ordering and anisotropic properties,” Adv. Mater., 2306800 (2023).