Involved in the uptake of the purine bases hypoxanthine and guanine. Expression is regulated by both purR and xptR regulons. Negatively regulated by hypoxanthine and guanine. Cells lacking this gene show normal growth on inosine as the purine source, normal hypoxanthine-guanine phosphoribosyltransferase activity, and are resistant to azaguanine. Belongs to the nucleobase:cation symporter-2 (NCS2) (TC 2.A.40) family. Azg-like subfamily.