Double hexameric ring assembly of the type III protein translocase ATPase HrcN.
The specialized type III secretion (T3S) apparatus of pathogenic and symbiotic Gram-negative bacteria comprises a complex transmembrane organelle and an ATPase homologous to the F1-ATPase beta subunit. The T3S ATPase HrcN of Pseudomonas syringae associates with the inner membrane, and its ATP hydrolytic activity is stimulated by dodecamerization. The structure of dodecameric HrcN (HrcN12) determined to 1.6 nm by cryo-electron microscopy is presented. HrcN12 comprises two hexameric rings that are probably stacked face-to-face by the association of their C-terminal domains. It is 11.5 +/- 1.0 nm in diameter, 12.0 +/- 2.0 nm high and has a 2.0-3.8 nm wide inner channel. This structure is compared to a homology model based on the structure of the F1-beta-ATPase. A model for its incorporation within the T3S apparatus is presented.
Müller
Shirley A
SA
M. E. Müller Institute for Structural Biology, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
Pozidis
Charalambos
C
Stone
Remington
R
Meesters
Christian
C
Chami
Mohamed
M
Engel
Andreas
A
Economou
Anastassios
A
Stahlberg
Henning
H
D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D003198:Computer Simulation; D020285:Cryoelectron Microscopy / Q000379:methods; D017348:Microscopy, Electron, Scanning Transmission / Q000379:methods; D008958:Models, Molecular; D008970:Molecular Weight; D020836:Protein Structure, Quaternary; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D044224:Pseudomonas syringae / Q000201:enzymology*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D000251:Adenosine Triphosphatases; D006180:Proton-Translocating ATPases