Involved in the export of arginine. Important to control the intracellular level of arginine and the correct balance between arginine and lysine. May also be involved in the export of canavanine (a plant-derived antimetabolite). L-arginine(in) = L-arginine(out) Monomer. Transcriptionally regulated by ArgP in response to the accumulation of intracellular arginine or canavanine. Lysine has a negative effect on the expression of argO. The cytoplasmic N-terminal domain is important for ArgO function in vivo, but not the periplasmic C-terminal region. A pair of conserved aspartate residues, located near the opposing edges of the cytoplasmic membrane, may play a pivotal role in facilitating transmembrane arginine flux. Disruption mutant is supersensitive to the arginine analog canavanine. Belongs to the LysE/ArgO transporter (TC 2.A.75) family.