Functions as substrate-specific channel for nucleosides and deoxynucleosides (PubMed:791677, PubMed:3276691, PubMed:2458926). Has a greater affinity for deoxynucleosides than for nucleosides, and does not transport free bases (PubMed:2458926). In addition, constitutes the receptor for colicin K and phage T6 (PubMed:791677, PubMed:3276691). (Microbial infection) Serves as a receptor for CdiA-STECO31, required for adhesion between E.coli expressing CdiA-STECO31 and this strain. Loss of susceptibility to contact-dependent growth inhibition by CdiA-STECO31. Belongs to the nucleoside-specific channel-forming outer membrane porin (Tsx) (TC 1.B.10) family.