Fig. 1: CDTb purification.

a Protocol diagram. b Density gradient without LMNG pretreatment. c Density gradient with LMNG pretreatment before chymotrypsin treatment. d Location of CDTb residue F774 involved in di-heptamer formation. e Density gradient for the F774L mutant. f Density gradient for the F774G mutant. Both F774L and F774G were purified without LMNG pretreatment.