6qvp

Crystal structure of the peptidoglycan-binding domain of SiiA from Salmonella enterica

spinqualitylabelsall models 6qvp, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6qvp is a 6 chain structure with sequence from "bacillus_typhimurium"_loeffler_1892 "bacillus typhimurium" loeffler 1892. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: PO4 NonStd Res: MSE Gene: siiA, DD95_13055, EIL76_22260 ("Bacillus typhimurium" Loeffler 1892) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Salmonella invasion is mediated by a concerted action of the Salmonella pathogenicity island 4 (SPI4)-encoded type one secretion system (T1SS) and the SPI1-encoded type three secretion system (T3SS-1). The SPI4-encoded T1SS consists of five proteins (SiiABCDF) and secretes the giant adhesin SiiE. Here, we investigated structure-function relationships in SiiA, a non-canonical T1SS subunit. We show that SiiA consists of a membrane domain, an intrinsically disordered periplasmic linker region and a folded globular periplasmic domain (SiiA-PD). The crystal structure of SiiA-PD displays homology to that of MotB and other peptidoglycan (PG)-binding domains. SiiA-PD binds PG in vitro, albeit at an acidic pH, only. Mutation of Arg162 impedes PG binding of SiiA and reduces Salmonella invasion efficacy. SiiA forms a complex with SiiB at the inner membrane (IM), and the observed SiiA-MotB homology is paralleled by a predicted SiiB-MotA homology. We show that, similar to MotAB, SiiAB translocates protons across the IM. Mutating Asp13 in SiiA impairs proton translocation. Overall, SiiA shares numerous properties with MotB. However, whereas MotAB uses the proton motif force (PMF) to energize the bacterial flagellum, it remains to be shown how usage of the PMF by SiiAB assists T1SS function and Salmonella invasion. This article is protected by copyright. All rights reserved. Structural and functional characterisation of SiiA, an auxiliary protein from the SPI4-encoded type 1 secretion system from Salmonella enterica.,Kirchweger P, Weiler S, Egerer-Sieber C, Blasl AT, Hoffmann S, Schmidt C, Sander N, Merker D, Gerlach RG, Hensel M, Muller YA Mol Microbiol. 2019 Aug 16. doi: 10.1111/mmi.14368. PMID:31419359 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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