ExbB

spinqualitylabelsall models ExbB pentamer complex with ExbD peptide (red) (PDB code 5zfu) Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D The Structure of ExbB Structure ExbB consists of three transmembrane domains (spanning from residues 16-39, 128-155 and 162-194), with two large portions of the protein representing the majority of the protein in the cytoplasm and two smaller portions in the periplasm. ExbB can exist in the TonB system either in a complex with ExbD (to a ratio of 3.5:1) or on its own (where no ExbD is present), which has been suggested to play a part in the diverse roles of TonB. ExbB has a similar sequence and physiological structure to TolQ and is therefore thought to be evolutionarily linked. Function ExbB is essential for TonB-dependent energy transduction as the absence of ExbB prevents TonB responding to the proton motive force, as well as the change of the high-affinity association of TonB for the outer membrane to the cytoplasmic membrane. Loss of ExbB function can be partially replaced by TolQ and vice versa - reduced activities of either of these proteins via a mutant form can be reversed by introducing double mutants.

3D structures of ExbB

Updated on 26-February-2023

TonB, ExbD – EcExbB + ExbD peptide – Escherichia coli – Cryo EM
TolQ – EcExbB + ExbD – Cryo EM
5sv1 – ExbB + ExbD peptide
5sv0, 5zfp – EcExbB
6ye4 – SmExbB – Serratia marsescens - Cryo EM
7ajq – SmExbB + ExbD - Cryo EM

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