Fig. 2: Structural comparison between TolC and homologous proteins in E. coli.

a Ribbon diagram of TolC (PDB code: 1EK9). TolC is assembled from three protomers; chain A is coloured blue, and chains B and C are coloured grey. b Ribbon diagram of the CusC protomer (PDB code: 4K7R, shown in orange) superimposed on chain A of TolC (PDB code: 1EK9, shown in blue). Z-score of the protein pair: 28.1, root mean square deviation (RMSD) of the alpha carbon atoms: 2.1 Å, amino acid sequence identity: 17%. c Ribbon diagram of the MdtP protomer (AlphaFold code: AF-P32714-F1-v4, shown in green) superimposed on chain A of TolC (PDB code: 1EK9, shown in blue). Z-score of the protein pair: 24.8, RMSD of the alpha carbon atoms: 3.4 Å, amino acid sequence identity: 15%. d Ribbon diagram of the MdtQ protomer (AlphaFold Code: AF-Q8X659-F1-v4, shown in pink) superimposed on TolC (PDB code: 1EK9, shown in blue). Z-score of the protein pair: 26.0, RMSD of the alpha carbon atoms: 3.4 Å, amino acid sequence identity: 12%. Structure superpositions and Z-scores were generated using DALI Pairwise structure comparison and visualization using PyMOL. Z-scores ascribe statistical significance to the similarity between two protein structures, with scores over 20 indicating the structures are homologous. OM outer membrane.