2.A.6.2.5
Fatty acid, bile salt, gonadal steroid, antibacterial peptide efflux pump, MtrCDE (Kamal et al., 2007). Opening of the outer membrane protein channel, MtrE, in the tripartite efflux pump, MtrCDE, is induced by interaction with the membrane fusion partner, MtrC (Janganan et al., 2011).  The crystal structure of the trimeric MtrE forms a vertical tunnel extending down contiguously from the outer membrane surface to the periplasmic end in the open conformational state of this channel (Lei et al. 2014). Coordination of substrate binding and protonation in MtrD controls the functionally rotating transport mechanism (Fairweather et al. 2021). The amino acyl sequence, N917-P927, plays a key role in modulating substrate access to the binding cleft and influences the overall orientation of the protein within the inner membrane necessary for optimal functioning (Chitsaz et al. 2021).