Fig. 2.

ProTα delivery potency cannot be recapitulated by simple oligomers of acidic residues. a Sequences of ProTα and charged peptide analogs that contain –30 or –44 net theoretical charge for comparison. All proteins contain a Gly-Ala inserted after the initial Met to minimize expression level differences. b Despite sharing the same net theoretical charge as that of ProTα, (−44)PolyD/E-Cre does not promote potent protein delivery. EC₅₀ is defined as the protein concentration at which 50% of analyzed HeLa-DsRed cells contain red fluorescence. Values and error bars represent the mean and standard deviation of three independent biological replicates performed on different days. EC₅₀ values were determined by nonlinear fit to the Hill equation, and are followed by the standard errors of the fit. Source data are available in the Source Data file