6YE4 image
Entry Detail
PDB ID:
6YE4
EMDB ID:
Keywords:
Title:
Structure of ExbB pentamer from Serratia marcescens by single particle cryo electron microscopy
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2020-03-24
Release Date:
2021-03-31
Method Details:
Experimental Method:
Resolution:
3.20 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Biopolymer transport protein ExbB
Chain IDs:A, B, C, D, E
Chain Length:287
Number of Molecules:5
Biological Source:Serratia marcescens
Ligand Molecules
Primary Citation
Structural and molecular determinants for the interaction of ExbB from Serratia marcescens and HasB, a TonB paralog.
Commun Biol 5 355 355 (2022)
PMID: 35418619 DOI: 10.1038/s42003-022-03306-y

Abstact

ExbB and ExbD are cytoplasmic membrane proteins that associate with TonB to convey the energy of the proton-motive force to outer membrane receptors in Gram-negative bacteria for iron uptake. The opportunistic pathogen Serratia marcescens (Sm) possesses both TonB and a heme-specific TonB paralog, HasB. ExbBSm has a long periplasmic extension absent in other bacteria such as E. coli (Ec). Long ExbB's are found in several genera of Alphaproteobacteria, most often in correlation with a hasB gene. We investigated specificity determinants of ExbBSm and HasB. We determined the cryo-EM structures of ExbBSm and of the ExbB-ExbDSm complex from S. marcescens. ExbBSm alone is a stable pentamer, and its complex includes two ExbD monomers. We showed that ExbBSm extension interacts with HasB and is involved in heme acquisition and we identified key residues in the membrane domain of ExbBSm and ExbBEc, essential for function and likely involved in the interaction with TonB/HasB. Our results shed light on the class of inner membrane energy machinery formed by ExbB, ExbD and HasB.

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