Fig. 4.
Cartoon models of the conformational identities of the non-reducing SDS-PAGE gel bands observed for the F(ab’)2 fragment (A) and the intact mAb (B). Stochastic unfolding in SDS of both of the Fab domains observed in both F(ab’)2 fragment and the intact mAb is followed by unfolding of the very stable CH3 domain in the Fc portion of the intact mAb to explain the 3 and 4 discrete molecular weight bands observed for the F(ab’)2 fragment and the intact h2E2 anti-cocaine mAb, respectively. More compact “Folded” domains are shown as filled circles or ellipses, while more extended “Unfolded” domains are depicted as larger, uneven cloud-like structures. Letter labeling of the gel bands is the same as used in Figs. 1A and 2.