2.A.59.1.1
Plasma membrane ACR3 arsenite exporter (AsIII:H⁺ antiporter) (Wysocki et al., 1997).  Catalyzes proton antiport with either arsenite or antimonite.  Cys151 is essential for transport activity, while Cys90 and Cys169 are important in trafficking (Maciaszczyk-Dziubinska et al. 2013).  Other residues important for folding, trafficking and/or activity have also been identified (Markowska et al. 2015). This protein has 10 TMSs with cytoplasmically oriented N- and C-termini, and a homology-based structural model of Acr3 using the crystal structure of the Yersinia frederiksenii homologue of the human bile acid sodium symporter, ASBT, has been constructed (Wawrzycka et al. 2016).