part_of TolC PDB:1EK9 TolC is a protein subunit of many multidrug efflux complexes in Gram negative bacteria. It is an outer membrane efflux protein and is constitutively open. Regulation of efflux activity is often at its periplasmic entrance by other components of the efflux complex. antibiotic_resistance ARO:3000237 TolC EmrAB-TolC EmrKY-TolC AcrAB-TolC AcrEF-TolC MacAB-TolC subunit of efflux pump conferring antibiotic resistance MdtABC-TolC MdtEF-TolC AcrEF-TolC confers resistance to ciprofloxacin Klebsiella pneumoniae KpnGH-TolC