sentence: The insensitivity of the Δ fkpA mutant to colicin M was not caused by structural changes in any of the proteins involved in colicin M uptake as transport of ferrichrome and sensitivity to albomycin and ϕ 80 require the same TonB , ExbB and ExbD proteins as sensitivity to colicin M. tolM mutants are mutated in fkpA .