Figure 1. The set of Qc-∆ truncation mutants, mapped onto the structure of a quaternary SNARE bundle.

The C-terminus of each Qc-∆ is indicated with boldface type, except for Qc1∆, which contains one additional aminoacyl residue that remains after cleavage of the C-terminal affinity tag used for purification. The transmembrane anchors of the Qa, Qb, and R-SNAREs are not depicted.