Figure 4.

Overview of the principal components of the tripartite assemblies. The primary and tertiary structures of the main group of proteins involved formation of tripartite efflux complexes and type 1 secretion systems. The coloring of the key structural features is the same on the primary and the 3D structure. (A) Outer membrane factor (OMF) family on the example of the Pseudomonas aeruginosa OprM channel monomer, based on the PDB ID 1WP1.²⁶⁹ (B) Periplasmic adaptor protein (PAP), also known as the Membrane Fusion Protein (MFP) family, on the example of the Pseudomonas aeruginosa MexA associating with the RND transporter MexB. Two conformers are presented based on the PDB ID 6TA6;²⁷⁰ see text in section 7.2 for details. (C) A representative RND-family transporter—MexB, from P. aeruginosa. Trimeric assembly based on PDB ID 6T7S.²⁷⁰ PN and PC—periplasmic or porter domain N-terminal and C-terminal subdomains; DN and DC—docking/funnel domain N- and C-terminal subdomains, respectively. See section 5.1 and Figures 5 and 6 for details. (D) A representative structure of the Major Facilitator Superfamily (MFS) transporter with 14-transmembrane helices based on the POT-family member PepTSo from Shewanella oneidensis. PBD ID 4UVM,²⁷¹ monomer presented. See Section Y for details. (E) A dimeric structure of the MacB transporter from E. coli based on PDB ID 5NIK.²⁷² (F) Representative structure of the ABC transporters involved in the formation of the type 1 Secretion system (T1SS), on the example of Hemolysin alpha exporter HlyB. Dimer structure based on a homology model derived from the peptidase containing ABC transporter PCAT1 structure (PBD ID 4RY2).²⁷³ For details see section 5.6. NBD, nucleotide binding domain; CLD, C39 like domain.