Biophysical Society Conference | Tahoe 2022

Molecular Biophysics of Membranes

Poster Abstracts

50-POS Board 13 SYNTHESIS OF LARGE, TRANSPORTABLE, BIO-MEMBRANES INCLUDING MEMBRANE PROTEINS FROM GAS PHASE BY MOLECULAR BEAM DEPOSITION Matthias Wilm 1 ; 1 University College Dublin, Conway Institute, Dublin, Ireland The aim was to synthesise transportable protein containing membranes of an inherently unlimited size using a nano-electrospray ion source. A nano-electrospray was directed towards the liquid meniscus of a 3 mm wide reservoir holding an aqueous buffer and some SM-2 Biobeads for detergent extraction. In several steps bipolar lipids, glycerol and detergent solubilised membrane proteins were sprayed onto the surface and incubated to remove the detergent from the surface layer. Finally, the correct conditions were found to allow for self- assembly of a single lipid bio-membrane containing the proteins. The layer covered the entire surface as verified by transmission electron microscopy. No denatured protein was found. Instead, the images correspond to a protein filled membrane. The protein initially used was the integral membrane protein ompG, a mono-molecular pore. Additionally, I used listeriolysin O to investigate whether the procedure is gentle enough to allow for non-covalent complex formation. Listeriolysin O assembles on membranes into ring shaped complexes of 30 or more units. These rings insert themselves into membranes and form large pores. Using this method the pores formed and their assembly process from monomers could be directly visualised in the electron microscope. With the help of nano-electrospray it is possible to synthesise large, transportable bio-membranes that contain intact membrane proteins. These membranes allow the study of bio- membranes of defined composition using electron- and light microscopy. In addition the membranes can be incorporated into technical devices to benefit from the unique biochemical properties of specific membrane proteins. References: M. Wilm, “Synthesis of Extended, Self- Assembled Biological Membranes containing Membrane Proteins from Gas Phase,” bioRxiv, vol. 23, pp. 661215, 2019M. Wilm, “Evidence for Membrane Complex Assembly in Nanoelectrospray Generated Lipid Bilayers,” bioRxiv, vol. 42, pp. 661231, 2019

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