Extended Data Fig. 4: Proton and water transport rates.
From: Single-chain heteropolymers transport protons selectively and rapidly
a, Representative stopped-flow fluorescence traces of RHP1-containing POPC LUVs after rapid exposure to a buffer of a higher pH value. The initial and final equilibrated pH values are 6.85 and 7.35, respectively. Vln was added before the measurements. b, Calculated permeability values of RHP1-containing LUVs at various RHP1-to-lipid ratios. Error bars are 1 s.d. (n = 3). c, d, Conductance (c) and initial proton transport rate (d) per RHP1 chain at various RHP1-to-lipid ratios. Error bars are 1 s.d. (n = 3). e, Stopped-flow fluorescence traces of RHP1-containing LUVs after rapid exposure to a buffer of a higher pH or pD value. The initial and final equilibrated pH values are 6.85 and 7.35, respectively, for the H2O-based assay. The initial and final pD values are 7.25 and 7.75, respectively, for the D2O-based assay. Vln was added to the RHP1-containing LUV solutions, except for the GramA-containing LUVs. f, Osmotic water permeability of Vln, GramA and RHP1+Vln in POPC LUVs at 7 °C. Vln (K+ channel) and GramA (proton/cations/water channel) are the negative and positive controls, respectively. GramA, Vln and RHP1 were added to the solutions of preformed LUVs. ‘Premixed’ denotes premixing of RHP1 and the lipid before the preparation of LUVs. Error bars are 1 s.d. (n = 7).
