2.A.1.2.5
Multidrug (14- and 15-membered macrolides, lincosamides, streptogramins, tetracyclines, daunomycin, ethidium bromide, etc.):H⁺ antiporter, LmrP. Two proton translocation pathways have been proposed (Bapna et al., 2007), but Schaedler and van Veen, 2010 have provided evidence that a flexible cation binding site in LmrP is associated with variable proton coupling. Basic residues R260 and K357 affect the conformational dynamics of LmrP (Wang and van Veen, 2012).  Basic residues, R260 and K357 control the conformational dynamics of the protein (Wang and van Veen 2012).  Also specifically catalyzes Ca²⁺:3H⁺ antiport with an affinity of 7 μM (Zhang et al. 2012). Two carboxylates (Asp-235 and Glu-327) are critical for Ca²⁺ binding.  Protonation drives major conformational switches (Masureel et al. 2013). The system exhibits plasticity in proton interactions, which is a consequence of the flexibility in the location of key residues that are responsible for proton/multidrug antiport (Nair et al. 2016).