Harnessing Membrane Protein Properties in Inorganic-Organic Hybrid Materials

This project will incorporate high-loadings of membrane proteins in robust abiotic surfactant-silica films to harness the proteins’ exceptional selectivities for transporting ions, water, or other species for solar-to-electrochemical energy conversion or water treatment applications. 

Our scientific and engineering objectives are to measure, understand, and exploit the molecular-level compositions, structures, dynamics, and interactions of functionally-active membrane protein molecules with surfactants and local host environments to develop new biologically-enabled materials with novel photo-responsive, catalytic, or transport properties. During the current reporting period (January 1, 2019 – April 30, 2021) we successfully tested our hypotheses (1) that synthetic nanostructured silica-surfactant materials represent a versatile and optimizable platform for integrating functionally active membrane proteins, such as proteorhodopsin, in high concentrations into robust abiotic host matrices with tunable properties, (2) that illumination of PR-containing nanostructured silica films would induce local conformational dynamics of the PR guest molecules that are correlated with native-like photocycle kinetics that are associated with H⁺ pumping; and (3) that molecular-level compositions, structures, and dynamics of membrane proteins, surfactants, and silica precursor species can be optimized to improve the macroscopic functional properties of PR in inorganic-organic host materials.

During the next period, we will exploit the synthesis and processing insights that we have obtained (1) to measure and understand the effects of non-native environments on PR structure and photocycle properties, (2) to tune such environments to optimize PR photocycle kinetics and H⁺ pumping in non-native environments, and (3) to align co-assembled proteorhodopsin molecules, stabilizing and structure-directing surfactants, and network-forming silica species into robust transparent nanostructured hybrid films with anisotropic H⁺ transport properties.