TolC-AcrA complex formation monitored by time dependent single-channel electrophysiology

Role of AcrAB-TolC and Its Components in Influx–Efflux Dynamics of QAC Drugs in Escherichia coli Revealed Using SHG Spectroscopy

“…There are existing biophysical, biochemical, and more recently electrophysiological studies demonstrating in vitro interactions between AcrA and TolC. − Earlier, it was believed that the periplasmic adaptor protein AcrA is essential to form a sealed conduit between AcrB and TolC. , But later, it was shown experimentally that AcrB and TolC can also interact directly without the need for AcrA because the periplasmic domain of AcrB extends deep into the periplasm and has geometry corresponding to the periplasmic entrance of TolC. ,,, Therefore, AcrB and TolC can form a bipartite complex as well. These bipartite complexes have likely expelled the MG molecules from the periplasm directly outside the cell, as MG efflux was evident in ΔAcrA/ΔAcrB when compared to ΔAcrAB.…”