2.A.6.2.6
Multiple drug; N-(3-oxododecanoyl)-L-homoserine lactone autoinducer efflux pump, MexB (functions with MexA (an MFP, 8.A.1) and OprM (an OMF, 1.B.17; see 2.A.6.2.21). All three interact with each other. MexA promotes assembly and stability of the complex (Nehme and Poole, 2007)). Exports β-lactams, fluoroquinolones, tetracycline, macrolides, chloramphenicol, biocides, and a toxic indole compound, CBR-4830, that targets the MreB actin (Robertson et al., 2007). Confers tolerance to tea tree oil and its monoterpene components Terpinen-4-ol, 1,8-cineole and α-terpineol (Papadopoulos et al., 2008) as well as the antimicrobial peptide, colistin (Pamp et al., 2008) (Mao et al., 2002; Poole, 2008). The crystal structure has been solved at 3.0 Å resolution (Sennhauser et al., 2009). The MexA-OprM complex has an elongated cylindrical appearance (Trépout et al., 2010).  Mutations affecting export of antibiotics with cytoplasmic targets have been identified (Ohene-Agyei et al. 2012). RND-type xenobiotic transporters recognize hydrophobic substrates such as organic solvents by their periplasmic domains and expel them to the external milieu (Li et al. 2006). Differential impacts of MexB mutations on substrate selectivity of the MexAB-OprM multidrug efflux pump have been reported (Middlemiss and Poole 2004). MexAB-OprM is one of four primary drug exporters in P. aeruginosa (Lorusso et al. 2022). A DB08385 variant is a promising inhibitor-like candidate against Pseudomonas aeruginosa antibiotic resistance (Bera et al. 2024).