6YE4

Structure of ExbB pentamer from Serratia marcescens by single particle cryo electron microscopy

Summary for 6YE4

• Entry DOI: 10.2210/pdb6ye4/pdb
• EMDB information: 10789
• Descriptor: Biopolymer transport protein ExbB, (1S)-2-{[{[(2R)-2,3-DIHYDROXYPROPYL]OXY}(HYDROXY)PHOSPHORYL]OXY}-1-[(PALMITOYLOXY)METHYL]ETHYL STEARATE (2 entities in total)
• Functional Keywords: membrane protein, iron uptake, proton transfer, tonb complex, metal transport
• Biological source: Serratia marcescens
• Total number of polymer chains: 5
• Total formula weight: 155823.22

Authors

Biou, V.,Delepelaire, P.,Coureux, P.D.,Chami, M. (deposition date: 2020-03-24, release date: 2021-03-31, Last modification date: 2024-07-10)

Primary citation

Biou, V.,Adaixo, R.J.D.,Chami, M.,Coureux, P.D.,Laurent, B.,Enguene, V.Y.N.,de Amorim, G.C.,Izadi-Pruneyre, N.,Malosse, C.,Chamot-Rooke, J.,Stahlberg, H.,Delepelaire, P.
Structural and molecular determinants for the interaction of ExbB from Serratia marcescens and HasB, a TonB paralog.
Commun Biol, 5:355-355, 2022

PubMed Abstract: 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. ExbB 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 ExbB and HasB. We determined the cryo-EM structures of ExbB and of the ExbB-ExbD complex from S. marcescens. ExbB alone is a stable pentamer, and its complex includes two ExbD monomers. We showed that ExbB extension interacts with HasB and is involved in heme acquisition and we identified key residues in the membrane domain of ExbB and ExbB, 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.

PubMed: 35418619
DOI: 10.1038/s42003-022-03306-y

Experimental method

ELECTRON MICROSCOPY (3.2 Å)