Nucleoside transport protein that can transport adenosine, uridine, thymidine, cytidine and deoxycytidine. Shows weak activity with inosine and xanthosine. Transport is driven by a proton motive force. Does not transport guanosine, deoxyguanosine, hypoxanthine or uracil. Also shows activity with the chemotherapeutic drugs 3'-azido-3'-deoxythymidine (AZT), 2',3'- dideoxycytidine (ddC) and 2'-deoxy-2',2'-difluorocytidine (gemcitabine)