Proteoliposomes as energy transferring nanomaterials: enhancing the spectral range of light-harvesting proteins using lipid-linked chromophores

• Published in: bioRxiv
• Main Authors: Hancock, Ashley M, Meredith, Sophie A, Connell, Simon D A, Jeuken, Lars J C, Adams, Peter G
• Format: Paper
• Language: English
• Published: Cold Spring Harbor Cold Spring Harbor Laboratory Press 25.04.2019
• Subjects: Chlorophyll; Chromophores; Light-harvesting complex; Light-harvesting proteins; Lipid membranes; Lipids; Nanomaterials; Nanotechnology; Proteins; Self-assembly
• DOI: 10.1101/609255

Biology provides a suite of optically-active nanomaterials in the form of 'light harvesting' protein-chlorophyll complexes, however, these have drawbacks including their limited spectral range. We report the generation of model lipid membranes (proteoliposomes) incorporating the photosynthetic protein Light-Harvesting Complex II (LHCII) and lipid-tethered Texas Red (TR) chromophores that act as a 'bio-hybrid' energy transferring nanomaterial. The effective spectral range of the protein is enhanced due to highly efficient energy transfer from the TR chromophores (up to 94%), producing a marked increase in LHCII fluorescence (up to 3x). Our self-assembly procedure offers excellent modularity allowing the incorporation of a range of concentrations of energy donors (TR) and acceptors (LHCII), allowing the energy transfer efficiency (ETE) and LHCII fluorescence to be tuned as desired. Fluorescence Lifetime Imaging Microscopy (FLIM) provides single-proteoliposome-level quantification of ETE, revealing distributions within the population and proving that functionality is maintained on a surface. Our membrane-based system acts as a controllable light harvesting nanomaterial with potential applications as thin films in photo-active devices.