Structure of the multidrug transporter EmrD from Escherichia coli.
EmrD is a multidrug transporter from the Major Facilitator Superfamily that expels amphipathic compounds across the inner membrane of Escherichia coli. Here, we report the x-ray structure of EmrD determined to a resolution of 3.5 angstroms. The structure reveals an interior that is composed mostly of hydrophobic residues, which is consistent with its role transporting amphipathic molecules. Two long loops extend into the inner leaflet side of the cell membrane. This region can serve to recognize and bind substrate directly from the lipid bilayer. We propose that multisubstrate specificity, binding, and transport are facilitated by these loop regions and the internal cavity.
Yin
Yong
Y
Scripps Research Institute, Department of Molecular Biology, 10550 North Torrey Pines Road, CB-105, La Jolla, CA 92037, USA.
He
Xiao
X
Szewczyk
Paul
P
Nguyen
That
T
Chang
Geoffrey
G