Nature provides a wide array of molecular machines that not only perform important biological functions, but also serve as potential building blocks for hybrid materials, devices, and systems. For example, bacteriorhodopsin (bR) is a transmembrane protein that functions as a light-gated proton pump as part of ATP synthesis and has been used in engineered systems for optical memory storage. Similarly, channelrhodopsin (cR) is a light-gated cation channel that has recently been used in optogenetic applications, such as remote control of neurons. Because both of these proteins use well-controlled photo-current generation, they could potentially serve as functional components of hybrid materials with enhanced optical and electrical properties. Central to this objective is the ability to engineer these proteins with specific characteristics to enable better understanding of the fundamental nature of these proteins as well as provide seamless integration into artificial environments. To this end, site-directed mutagenesis (SDM) was used to create mutations involving single amino acids that are to achieve novel function of these proteins in hybrid nanomaterials. This presentation will discuss the selection, modification, and function of specific mutations in both bR and cR. More specifically, mutational changes to bR will be discussed in terms of creating unique “chemical handles” for directed orientation bR on functionalized polycarbonate surfaces, as well as a mutation (Asp-85 residue with Thr) that enables bR to pump chlorine ions inward and protons outward under green light and reversibly, proton pumping inward under white light. The use of SDM in cR to mutate residues Cys-128 and Asp-156, which have a large effect on the conducting state and photocycle kinetics of cR, will also be presented.<br/><br/><i>Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.</i>

Engineering light-gated, transmembrane proteins for use in hybrid systems

249th National Meeting (2015)

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