Figure 2. MakA asymmetric dimer.

a) Atomic model of one asymmetric dimer consisting of chain A (green) and chain B (cyan) from the detergent-associated MakA structure. b) Comparison of the secondary structures of chain A, chain B from the detergent-associated MakA structure with the MakA soluble form. c) Chain A colored in a rainbow gradient from the N-terminus (blue) to the C-terminus (red). d) Chain B colored in a rainbow gradient from the N-terminus (blue) to the C-terminus (red). e) Superimposition of chain A and chain B. f) Superimposition of chain A with the MakA soluble form (PDB: 6EZV). g) Superimposition of chain B with the MakA soluble form (PDB: 6EZV). h) Proposed structural rearrangement from the soluble form to chain B and then to chain A. The transition from soluble to transmembrane form of MakA chain B involves the rotation of the pre- and post-β-tongue helices (yellow and orange, respectively) away from the core soluble domain (cyan), as well as the extension and refolding of the β-tongue (blue) into α helices. i) Superimposition of the detergent-associated MakA asymmetric dimer with the asymmetric dimer from the MakA helical assembly (PDB: 7P3R).