2.A.75.1.2
L-arginine exporter (ArgO or YggA) (Nandineni and Gowrishankar 2004).  ArgP-ArgO of E. coli exhibits transcriptional cross activity with the corresponding pair, LysG-LysE of Corynebacterium glutamicum (Marbaniang and Gowrishankar 2012).  ArgO when overproducted confers sensitivity to the toxic arginine analogue, canavanine and catalyzes export of L-lysine (Pathania and Sardesai 2015). ArgO assumes an Nin-Cout configuration, potentially forming a five-transmembrane helix bundle flanked by a cytoplasmic N-terminal domain (NTD) comprising roughly its first 38 to 43 amino acyl residues and a short periplasmic C-terminal region (CTR). Mutagenesis studies indicate that the CTR, but not the NTD, is dispensable for ArgO function in vivo, and that a pair of conserved aspartate residues, located near the opposing edges of the cytoplasmic membrane, may play a pivotal role in facilitating transmembrane Arg flux (Pathania et al. 2016). ArgO possesses a membrane topology that is distinct from that reported for LysE, with substantial variation in the topological arrangement of the proximal one-third portions of the two exporters. The Arg-translocating conduit is formed by a monomer of ArgO (Pathania et al. 2016).