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Fig. 1 | BMC Biology

Fig. 1

From: Role of electrostatic interactions for ligand recognition and specificity of peptide transporters

Fig. 1

Functional characterization of YePEPT. a Kinetics of YePEPT-mediated [3H]Ala-Ala uptake in E. coli cells. Uptake of the radioligand in E. coli cells transformed with the YePEPT construct (YePEPT) and the empty vector (vector; control) is shown. The determined Km is indicated. Error bars represent SEM from triplicates. One representative experiment from three similar independent experiments is shown. b Co-transport ion and substrate chain length dependence of uptake: Na+ dependence was assessed by replacing Na+ with choline (−Na+); and H+ dependence by addition of the proton-ionophore carbonyl cyanide 3-chlorophenylhydrazone (CCCP). Chain length dependence was assessed with L-Ala and the corresponding di-, tri- and tetrapeptides as competitors (10 mM final concentration). c Substrate specificity of YePEPT by competition assay (2.5 mM final concentration). Error bars in (b) and (c) represent SEM from at least three independent experiments, each in triplicate. d Ki determination of YePEPT for Asp-Ala. The determined Ki is indicated (95 % confidence intervals: 46–126 μM). Error bars represent SEM from triplicates. One representative experiment from three similar independent experiments is shown

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