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. Author manuscript; available in PMC: 2013 Aug 28.
Published in final edited form as: Biochemistry. 2012 Aug 15;51(34):6753–6759. doi: 10.1021/bi300493u

Figure 3.

Figure 3

Trypsin treatment of whole FhuA in the presence of 4 M urea resulted in a faster-migrating band on SDS-PAGE (see Materials and Methods for details of the trypsin treatment). Whole FhuA protein migrates at ~80 kDa when boiled in either buffer or urea, as shown in lanes 1 and 4 (numbers at bottom of figure). In the presence of trypsin alone (lane 2), there may be a very faint band representing a faster migrating species, whereas trypsin and urea together (lane 5) converted about half of the 80 kDa band to the faster migrating species. A preincubation of trypsin with soybean trypsin inhibitor resulted in no faster migrating species (lanes 3 and 6).