5WQ7

CryoEM structure of type II secretion system secretin GspD in E.coli K12

Summary for 5WQ7

• Entry DOI: 10.2210/pdb5wq7/pdb
• Related: 5WQ8 5WQ9
• EMDB information: 6675
• Descriptor: Putative type II secretion system protein D (1 entity in total)
• Functional Keywords: secretin family, c15 symmetry, t2ss, protein transport
• Biological source: Escherichia coli K-12
• Total number of polymer chains: 15
• Total formula weight: 1026161.84

Authors

Yan, Z.,Yin, M.,Li, X. (deposition date: 2016-11-23, release date: 2016-12-28, Last modification date: 2024-03-27)

Primary citation

Yan, Z.,Yin, M.,Xu, D.,Zhu, Y.,Li, X.
Structural insights into the secretin translocation channel in the type II secretion system
Nat. Struct. Mol. Biol., 24:177-183, 2017

PubMed Abstract: The secretin GspD of the type II secretion system (T2SS) forms a channel across the outer membrane in Gram-negative bacteria to transport substrates from the periplasm to the extracellular milieu. The lack of an atomic-resolution structure of the GspD channel hinders the investigation of substrate translocation mechanism of T2SS. Here we report cryo-EM structures of two GspD channels (∼1 MDa), from Escherichia coli K12 and Vibrio cholerae, at ∼3 Å resolution. The structures reveal a pentadecameric channel architecture, wherein three rings of GspD N domains form the periplasmic channel. The secretin domain constitutes a novel double β-barrel channel, with at least 60 β-strands in each barrel, and is stabilized by S domains. The outer membrane channel is sealed by β-strand-enriched gates. On the basis of the partially open state captured, we proposed a detailed gate-opening mechanism. Our structures provide a structural basis for understanding the secretin superfamily and the mechanism of substrate translocation in T2SS.

PubMed: 28067918
DOI: 10.1038/nsmb.3350

Experimental method

ELECTRON MICROSCOPY (3.04 Å)