Ion Channel Activity of Transmembrane Segment 6 of Escherichia coli Proton-Dependent Manganese Transporter
Abstract
Synthetic peptide corresponding to transmembrane segment TMS6 of secondary-active transporter MntH from Escherichia coli was used as a suitable alternative model enabling to study TMS structure, TMS interaction with membranes and also function of MntH. The secondary structure of the peptides was estimated in different environments using circular dichroism spectroscopy.
These peptides interacted with and adopted helical conformation in lipid membranes. Electrophysiological experiments demonstrated that individual TMS were able under certain conditions to form ion channels in model biological membranes.
Electrophysiological properties of these weakly cation-selective ion channels were strongly dependent on surrounding pH and the presence of manganese ion, as physiological substrate of MntH.