Transport of lipopolysaccharides (LPS) to the surface of the outer membrane is essential for viability of Gram-negative bacteria. Periplasmic LptC and LptA proteins of the LPS transport system (Lpt) are responsible for LPS transfer between the Lpt inner and outer membrane complexes. Here, using a monomeric E. coli LptA mutant, we first show in vivo that a stable LptA oligomeric form is not strictly essential for bacteria. The LptC-LptA complex was characterized by a combination of SAXS and NMR methods and a low resolution model of the complex was determined. We were then able to observe interaction of LPS with LptC, the monomeric LptA mutant as well as with the LptC-LptA complex. A LptC-LPS complex was built based on NMR data in which the lipid moiety of the LPS is buried at the interface of the two Î²-jellyrolls of the LptC dimer. The selectivity of LPS for this intermolecular surface and the observation of such cavities at homo- or heteromolecular interfaces in LptC and LptA suggests that intermolecular sites are essential for binding LPS during its transport.
Interaction of lipopolysaccharides at intermolecular sites of the periplasmic Lpt transport assembly / C. Laguri, P. Sperandeo, K. Pounot, I. Ayala, A. Silipo, C.M. Bougault, A. Molinaro, A. Polissi, J. Simorre. - In: SCIENTIFIC REPORTS. - ISSN 2045-2322. - 7:1(2017), pp. 9715.1-9715.13.
|Titolo:||Interaction of lipopolysaccharides at intermolecular sites of the periplasmic Lpt transport assembly|
|Settore Scientifico Disciplinare:||Settore BIO/19 - Microbiologia Generale|
|Data di pubblicazione:||2017|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1038/s41598-017-10136-0|
|Appare nelle tipologie:||01 - Articolo su periodico|