AI Article Synopsis
- The type II secretion system (T2SS) is crucial for Gram-negative bacteria to transport folded proteins out of their cells, involving complex protein machinery.
- Researchers have successfully characterized the GspE (EpsE) component of T2SS as a hexamer when fused with another protein, Hcp1, using native mass spectrometry.
- The study demonstrates that the fused complex exhibits significantly enhanced enzymatic activity compared to the individual GspE monomers, revealing diverse structural configurations and potential variability within the hexameric assemblies.
Article Abstract
The type II secretion system (T2SS), a multiprotein machinery spanning two membranes in Gram-negative bacteria, is responsible for the secretion of folded proteins from the periplasm across the outer membrane. The critical multidomain T2SS assembly ATPase GspE(EpsE) had not been structurally characterized as a hexamer. Here, four hexamers of Vibrio cholerae GspE(EpsE) are obtained when fused to Hcp1 as an assistant hexamer, as shown with native mass spectrometry. The enzymatic activity of the GspE(EpsE)-Hcp1 fusions is ∼20 times higher than that of a GspE(EpsE) monomer, indicating that increasing the local concentration of GspE(EpsE) by the fusion strategy was successful. Crystal structures of GspE(EpsE)-Hcp1 fusions with different linker lengths reveal regular and elongated hexamers of GspE(EpsE) with major differences in domain orientation within subunits, and in subunit assembly. SAXS studies on GspE(EpsE)-Hcp1 fusions suggest that even further variability in GspE(EpsE) hexamer architecture is likely.
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|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3775503 | PMC |
| http://dx.doi.org/10.1016/j.str.2013.06.027 | DOI Listing |
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