Fig 4.

Comparing the stabilities of BxpB trimers and trimers of the BclA CTD. Samples of BxpB trimers in either Xa buffer or PBS and BclA CTD trimers in Xa buffer were made 1× in sample buffer. Portions of the BclA CTD trimer sample were heated at the indicated temperatures for 8 min. A fraction of each sample containing approximately the same amount of protein was analyzed by SDS-PAGE; the Coomassie-stained gel is shown. Filled and open arrowheads indicate the positions of trimeric and monomeric BclA, respectively. Trimers of the BclA CTD migrate faster than predicted from their mass, as previously described (12). The molecular masses of protein standards are indicated.