(449bk) Membrane Protein Insertion and Compatibility with Biomimetic Membranes
Here, we propose and test methods to evaluate membrane protein and membrane protein-mimic compatibility with biomimetic membranes. We conducted biophysical activity characterization using stopped-flow spectroscopy, membrane protein density determination using Fluorescence Correlation Spectroscopy (FCS), and evaluation of the effect of matrix hydrophobicity on protein insertion using a new distyrylbenzene chromophore optical characterization technique. Combined the methods utilized provided single protein activity, and for a first time a quantitative measure of the chemical and physical compatibility between proteins and membranes. Water transport protein (aquaporins, AQPs), rhodopsins, and artificial water channels (specifically peptide-appended pillar[n]arene (PAP) channels) were reconstituted into a range of biomimetic membrane matrices to evaluate the proposed platform. Compatibility measurement results showed that both AQPs and PAP8 channels preserve their single molecule water transport rates in different biomimetic membranes while their reconstitution density changes leading to different membrane permeability. We also show that membrane protein reconstitution density correlates with hydrophobicity mismatch between membrane protein and biomimetic membranes: smaller hydrophobicity mismatch between the membrane matrix and the proteins lead to higher membrane protein (or membrane protein-mimic) reconstitution densities.
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