Localization of the binding site of an antibody affecting ATPase activity of chaperonin cpn60 from Bordetella pertussis

Imaging processing has revealed the attachment site of antibody 54G8 on chaperonin 60 (cpn60) from Bordetella pertussis. This antibody, previously shown to affect the ability of chaperonin 10 (cpn10) to inhibit the ATPase activity of cpn60, is attached at the ends of the cpn60 and links the molecules into long chains. When only Fab fragments, which also affect ATPase activity, are used for labeling, these attach to both ends of the cpn60 molecule, but the long chains are not seen. Some perturbation of cpn60 was seen when Fab fragments were bound (Fab:cpn60 = 28:1).