Publication Date
7-7-2023
Journal
Nature Communications
DOI
10.1038/s41467-023-39583-2
PMID
37419909
PMCID
PMC10329019
PubMedCentral® Posted Date
7-7-2023
PubMedCentral® Full Text Version
Post-print
Published Open-Access
yes
Keywords
Type II Secretion Systems, Secretin, Escherichia coli, Escherichia coli Proteins, Bacterial Proteins, Bacterial Outer Membrane Proteins, Cryoelectron tomography, Bacterial secretion, Structural biology
Abstract
The GspD secretin is the outer membrane channel of the bacterial type II secretion system (T2SS) which secrets diverse toxins that cause severe diseases such as diarrhea and cholera. GspD needs to translocate from the inner to the outer membrane to exert its function, and this process is an essential step for T2SS to assemble. Here, we investigate two types of secretins discovered so far in Escherichia coli, GspDα, and GspDβ. By electron cryotomography subtomogram averaging, we determine in situ structures of key intermediate states of GspDα and GspDβ in the translocation process, with resolution ranging from 9 Å to 19 Å. In our results, GspDα and GspDβ present entirely different membrane interaction patterns and ways of transitioning the peptidoglycan layer. From this, we hypothesize two distinct models for the membrane translocation of GspDα and GspDβ, providing a comprehensive perspective on the inner to outer membrane biogenesis of T2SS secretins.
Comments
This article has been corrected. See Nat Commun. 2023 Aug 10;14:4833.
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