6HCG

Klebsiella pneumoniae type II secretion system outer membrane complex. PulD, PulS and PulC HR domain.

Summary for 6HCG

• Entry DOI: 10.2210/pdb6hcg/pdb
• EMDB information: 0193
• Descriptor: Type II secretion system protein D, Pullulanase, Pectic enzymes secretion protein OutC (3 entities in total)
• Functional Keywords: type ii secretion system, secretin, outer membrane channel, protein transport
• Biological source: Klebsiella pneumoniae; More
• Total number of polymer chains: 45
• Total formula weight: 1746711.08

Authors

Chernyatina, A.A.,Low, H.H. (deposition date: 2018-08-15, release date: 2019-11-27, Last modification date: 2024-11-13)

Primary citation

Chernyatina, A.A.,Low, H.H.
Core architecture of a bacterial type II secretion system.
Nat Commun, 10:5437-5437, 2019

PubMed Abstract: Bacterial type II secretion systems (T2SSs) translocate virulence factors, toxins and enzymes across the cell outer membrane. Here we use negative stain and cryo-electron microscopy to reveal the core architecture of an assembled T2SS from the pathogen Klebsiella pneumoniae. We show that 7 proteins form a ~2.4 MDa complex that spans the cell envelope. The outer membrane complex includes the secretin PulD, with all domains modelled, and the pilotin PulS. The inner membrane assembly platform components PulC, PulE, PulL, PulM and PulN have a relative stoichiometric ratio of 2:1:1:1:1. The PulE ATPase, PulL and PulM combine to form a flexible hexameric hub. Symmetry mismatch between the outer membrane complex and assembly platform is overcome by PulC linkers spanning the periplasm, with PulC HR domains binding independently at the secretin base. Our results show that the T2SS has a highly dynamic modular architecture, with implication for pseudo-pilus assembly and substrate loading.

PubMed: 31780649
DOI: 10.1038/s41467-019-13301-3

Experimental method

ELECTRON MICROSCOPY (4.3 Å)