Organization of protein domains in MinE and model of the cross-β structure formed by the amyloidogenic region of MinE.
(A) The MinE protein can be divided into three functional domains, a membrane-binding domain that contains a membrane-induced amphipathic helix and basic residues, a bifunctional domain that interacts with MinD in an α-helical conformation and self-assembles in a β-stranded conformation, and a dimerization domain at the C-terminus. The dimerization domain is also known as the topological specificity domain. (B) Illustration of the cross-β structure formed by the amyloidogenic region of MinE (19–28); the alternating β strands are colored green and yellow for clarity. (C) RMSD plots of α-carbon and main-chain atoms from a 5-ns simulation to demonstrate conformational equilibrium. (D) Frontal view of the cross-β structure of the amyloidogenic region of MinE1-31; only the backbone of the molecule and the side chains facing the hydrophobic interface are shown. (E) Top view of the model showing anti-parallel arrangements of the residues in the amyloidogenic region; residues containing side chains facing the hydrophobic interface of two β sheets are shown in red.