Sandbox Reserved 689

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This Sandbox is Reserved from 30/01/2013, through 30/12/2013 for use in the course "Biochemistry II" taught by Hannah Tims at the Messiah College. This reservation includes Sandbox Reserved 686 through Sandbox Reserved 700.

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Contents 1 The E. coli AcrB Efflux Pump 2 Structural Elements 3 Substrates 4 Energy Transduction

The E. coli AcrB Efflux Pump

spinqualitylabelsall models Asymmetrical AcrB Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Structure

The is part of a tripartite system used by E. Coli to remove antibiotic and other toxic molecules from the bacterial cell. It works in tandem with , an outer membrane pore can be recruited for many purposes. The beta barrel at the top of the TolC protein spans the outer membrane, allowing the drug to exit the bacterium.

Structural Elements

Substrates

Because of the large binding pockets in AcrB, it is able to bind and export a wide variety of antibiotic drugs and other toxins.

Rifampicin is a high molecular weight drug (~800 g/mol) that has been crystallized in the proximal binding pocket

, interacting residues (all residues within 4 Angstroms) highlighted and shown in ball-and-stick representation.

interacting residues are shown here (Polar in blue, nonpolar in orange).

(switch loop is shown in orange).

(Rifampicin crystal structure from Nakashima, et al. 2011)

Minocycline is a lower molecular weight drug (~400 g/mol) that has been crystallized in the .

(switch loop shown in green)

(blue=polar, green=aliphatic, orange=hydrophobic).

Energy Transduction

There are (Asp408, Asp407, Lys940, and Arg 971) whose protonation and deprotonation are suggested to play a large role in the conformational change between the L, T, and O states (Eicher, et al. 2009). PDB: 3D9B