Characterization of lipopolysaccharide transport protein complex

Quanju Xiang, Haiyan Wang, Zhongshan Wang, Yizheng Zhang, Changjiang Dong

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6 Citations (Scopus)


Lipopolysaccharide (LPS) is an essential component of the outer membranes (OM) of most Gram-negative bacteria, which plays a crucial role in protection of the bacteria from toxic compounds and harsh conditions. The LPS is biosynthesized at the cytoplasmic side of inner membrane (IM), and then transported across the aqueous periplasmic compartment and assembled correctly at the outer membrane. This process is accomplished by seven LPS transport proteins (LptA-G), but the transport mechanism remains poorly understood. Here, we present findings by pull down assays in which the periplasmic component LptA interacts with both the IM complex LptBFGC and the OM complex LptDE in vitro, but not with complex LptBFG. Using purified Lpt proteins, we have successfully reconstituted the seven transport proteins as a complex in vitro. In addition, the LptC may play an essential role in regulating the conformation of LptBFG to secure the lipopolysaccharide from the inner membrane. Our results contribute to the understanding of lipopolysaccharide transport mechanism and will provide a platform to study the detailed mechanism of the LPS transport in vitro.
Original languageEnglish
Pages (from-to)131-138
JournalCentral European Journal of Biology
Issue number2
Early online date9 Nov 2013
Publication statusPublished - Feb 2014


  • Protein Interactions
  • Protein complex
  • Pull down
  • Protease treatment
  • Crosslinker

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