FIG. 5.

Purification of YqjI. Overexpressed YqjI eluted as two peaks during heparin column chromatography (gray trace). The addition of 500 μM NiCl₂ to LB during cell growth and protein expression did not alter the subsequent YqjI elution profile (black trace). The first YqjI elution peak contained monomeric YqjI, while the second elution peak contained an oligomeric form of YqjI that is likely tetrameric or a higher quaternary structure (as subsequently determined by gel filtration chromatography). AU₂₈₀, absorbance at 280 nm.