B, Normalized fluorescence intensity profiles across E. coli JM83 cell widths for CCCP and/or trypsin treated cells. Fluorescence was measured in ImageJ for 15 cells per condition and normalised to more clearly show distribution profiles for each condition. CCCP-treated cells showed peripheral ColE9* K469CAF647 fluorescence consistent with the colicin being bound at the OM. Trypsin treatment of cells in the absence of CCCP results in loss of this peripheral fluorescence but the presence of mid-cell signal consistent with internalisation. Treatment with CCCP and trypsin removed all ColE9* K469CAF647 fluorescence from cells, as in a. Error bars represent % SEM. 