title: Optimization of bacteriorhodopsin for bioelectronic devices.
abstract: Bacteriorhodopsin (BR) is the photoactive proton pump found in the purple membrane of the salt marsh archaeon Halobacterium salinarum. Evolution has optimized this protein for high photochemical efficiency, thermal stability and cyclicity, as the organism must be able to function in a hot, stagnant and resource-limited environment. Photonic materials generated via organic chemistry have yet to surpass the native protein in terms of quantum efficiency or cyclicity. However, the native protein still lacks the overall efficiency necessary for commercial viability and virtually all successful photonic devices using bacteriorhodopsin are based on chemical or genetic variants of the native protein. We show that genetic engineering can provide significant improvement in the device capabilities of proteins and, in the case of bacteriorhodopsin, a 700-fold improvement has been realized in volumetric data storage. We conclude that semi-random mutagenesis and directed evolution will play a prominent role in future efforts in bioelectronic optimization.
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Wise
authors.forename: Nathan B
authors.initials: NB
authors.lastname: Gillespie
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Stuart
authors.forename: Mark P
authors.initials: MP
authors.lastname: Krebs
authors.forename: Robert R
authors.initials: RR
authors.lastname: Birge
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry* / Q000235:genetics* / Q000528:radiation effects; D001672:Biocompatible Materials; D019020:Directed Molecular Evolution / Q000379:methods*; D004563:Electrochemistry; D004581:Electronics / Q000295:instrumentation*; D019617:Halobacterium salinarum / Q000378:metabolism; D021621:Imaging, Three-Dimensional / Q000295:instrumentation; D016247:Information Storage and Retrieval / Q000379:methods*; D008027:Light; D008904:Miniaturization; D016297:Mutagenesis, Site-Directed; D036103:Nanotechnology; D055095:Optics and Photonics / Q000295:instrumentation; D010777:Photochemistry; D015202:Protein Engineering / Q000379:methods*; D011786:Quality Control
chemical_list: D001672:Biocompatible Materials; D001436:Bacteriorhodopsins