| Structural highlights
Function
[LPTE_ECOLI] Together with LptD, is involved in the assembly of lipopolysaccharide (LPS) at the surface of the outer membrane. Required for the proper assembly of LptD. Binds LPS and may serve as the LPS recognition site at the outer membrane.[1] [2] [3]
Publication Abstract from PubMed
The assembly of lipopolysaccharide (LPS) on the surface of Gram-negative bacterial cells is essential for their viability and is achieved by the seven-protein LPS transport (Lpt) pathway. The outer membrane (OM) lipoprotein LptE and the beta-barrel membrane protein LptD form a complex that assembles LPS into the outer leaflet of the OM. We report a crystal structure of the Escherichia coli OM lipoprotein LptE at 2.34 A. The structure reveals homology to eukaryotic LPS-binding proteins and allowed for the prediction of an LPS-binding site, which was confirmed by genetic and biophysical experiments. Specific point mutations at this site lead to defects in OM biogenesis. We show that wild-type LptE disrupts LPS-LPS interactions in vitro and that these mutations decrease the ability of LptE to disaggregate LPS. Transmission electron microscopic imaging shows that LptE can disrupt LPS aggregates even at substoichiometric concentrations. We propose a model in which LptE functions as an LPS transfer protein in the OM translocon by disaggregating LPS during transport to allow for its insertion into the OM.
LptE binds to and alters the physical state of LPS to catalyze its assembly at the cell surface.,Malojcic G, Andres D, Grabowicz M, George AH, Ruiz N, Silhavy TJ, Kahne D Proc Natl Acad Sci U S A. 2014 Jul 1;111(26):9467-72. doi:, 10.1073/pnas.1402746111. Epub 2014 Jun 17. PMID:24938785[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Wu T, McCandlish AC, Gronenberg LS, Chng SS, Silhavy TJ, Kahne D. Identification of a protein complex that assembles lipopolysaccharide in the outer membrane of Escherichia coli. Proc Natl Acad Sci U S A. 2006 Aug 1;103(31):11754-9. Epub 2006 Jul 21. PMID:16861298 doi:http://dx.doi.org/0604744103
- ↑ Sperandeo P, Lau FK, Carpentieri A, De Castro C, Molinaro A, Deho G, Silhavy TJ, Polissi A. Functional analysis of the protein machinery required for transport of lipopolysaccharide to the outer membrane of Escherichia coli. J Bacteriol. 2008 Jul;190(13):4460-9. Epub 2008 Apr 18. PMID:18424520 doi:JB.00270-08
- ↑ Chng SS, Ruiz N, Chimalakonda G, Silhavy TJ, Kahne D. Characterization of the two-protein complex in Escherichia coli responsible for lipopolysaccharide assembly at the outer membrane. Proc Natl Acad Sci U S A. 2010 Mar 23;107(12):5363-8. doi:, 10.1073/pnas.0912872107. Epub 2010 Mar 4. PMID:20203010 doi:http://dx.doi.org/10.1073/pnas.0912872107
- ↑ Malojcic G, Andres D, Grabowicz M, George AH, Ruiz N, Silhavy TJ, Kahne D. LptE binds to and alters the physical state of LPS to catalyze its assembly at the cell surface. Proc Natl Acad Sci U S A. 2014 Jul 1;111(26):9467-72. doi:, 10.1073/pnas.1402746111. Epub 2014 Jun 17. PMID:24938785 doi:http://dx.doi.org/10.1073/pnas.1402746111
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