8DCK

Structure of hemolysin A secretion system HlyB/D complex, ATP-bound

Summary for 8DCK

• Entry DOI: 10.2210/pdb8dck/pdb
• EMDB information: 27326
• Descriptor: Alpha-hemolysin translocation ATP-binding protein HlyB, Membrane fusion protein (MFP) family protein, ADENOSINE-5'-TRIPHOSPHATE, ... (4 entities in total)
• Functional Keywords: hydrolase, transport, membrane protein
• Biological source: Escherichia coli CFT073; More
• Total number of polymer chains: 12
• Total formula weight: 808941.95

Authors

Zhao, H.,Chen, J. (deposition date: 2022-06-16, release date: 2022-09-14, Last modification date: 2024-06-12)

Primary citation

Zhao, H.,Lee, J.,Chen, J.
The hemolysin A secretion system is a multi-engine pump containing three ABC transporters.
Cell, 185:3329-3340.e13, 2022

PubMed Abstract: Type 1 secretion systems (T1SSs) are widespread in pathogenic Gram-negative bacteria, extruding protein substrates following synthesis of the entire polypeptide. The Escherichia coli hemolysin A secretion system has long been considered a prototype in structural and mechanistic studies of T1SSs. Three membrane proteins-an inner membrane ABC transporter HlyB, an adaptor protein HlyD, and an outer membrane porin TolC-are required for secretion. However, the stoichiometry and structure of the complex are unknown. Here, cryo-electron microscopy (cryo-EM) structures determined in two conformations reveal that the inner membrane complex is a hetero-dodecameric assembly comprising three HlyB homodimers and six HlyD subunits. Functional studies indicate that oligomerization of HlyB and HlyD is essential for protein secretion and that polypeptides translocate through a canonical ABC transporter pathway in HlyB. Our data suggest that T1SSs entail three ABC transporters, one that functions as a protein channel and two that allosterically power the translocation process.

PubMed: 36055198
DOI: 10.1016/j.cell.2022.07.017

Experimental method

ELECTRON MICROSCOPY (3.4 Å)