Figure 7: Loss of leader sequences blocks function of McpM.
From: Microcin PDI regulation and proteolytic cleavage are unique among known microcins
(A) Schematic diagram of different deleted constructs where residue numbering corresponds to amino acids in the full-length, wild-type McpM. ColV1–15 is the signal peptide sequence from colicin V. (B) Competition assays between the different deleted mutants and BW25113 (vector control). Deletion mutants were made in an E25∆mcpM∆mcpA and the modified recombinant protein was expressed in trans by using p207 (Table S1). Results are expressed as the mean difference in CFU of the sensitive strain grown in co-culture and monoculture (error bars = SEM; 3 independent replicates). *Significant ANOVA followed by a Dunnett’s one-way multiple comparisons test versus control group (Wild-type) (P < 0.01). (C) Western blot analysis of McpM that was precipitated from culture media. Lane 1: E.coli-25 (E25); Lane 2: E25∆mcpM∆mcpA(McpM∆19-36); Lane 3: E25∆mcpM∆mcpA (McpM A36D); Lane 4: E25∆mcpM∆mcpB (mcpM).
