sentence: However , compared with C3bot alone ( Fig 1C , bottom ) , activity of the fusion toxin ( Fig 1C , top ) was much weaker , most likely , because in the chimeric fusion protein , C3bot is packed within the BC3 cocoon.To gain insight into the question of whether the cocoon shields the toxin from its substrate and / or co-substrate , we incubated Photorhabdus BC3 at elevated temperatures ( 4 ° C , 40 ° C , and 95 ° C ) to destroy the cocoon , cooled the samples down to 21 ° C again , and performed in vitro ADP-ribosylation of actin .