title: A phosphoethanolamine transferase specific for the 4'-phosphate residue of Cronobacter sakazakii lipid A.
abstract: OBJECTIVE
  Investigate how Cronobacter sakazakii modify their lipid A structure to avoid recognition by the host immune cells.
  
  
  RESULTS
  Lipid A modification was observed in C. sakazakii BAA894 grown at pH 5·0 but not pH 7·0. Overexpression of C. sakazakii gene ESA_RS09200 in Escherichia coli W3110 caused a phosphoethanolamine (PEA) modification of lipid A; when ESA_RS09200 was deleted in C. sakazakii BAA894, this lipid A modification disappeared. Lipid A modification was observed in BAA894 grown at pH 5·0 when the 1- phosphate residue of lipid A was removed, but disappeared when the 4'- phosphate residue of lipid A was removed. When ESA_RS16430, the orthologous gene of E. coli pmrA, was deleted in C. sakazakii BAA894, this PEA modification of lipid A was still observed, suggesting that this modification was not regulated by the PmrA-PmrB system. Compared to the wild-type BAA894, ESA_RS09200 deletion mutant showed decreased resistance to cationic antimicrobial peptides (CAMP), increased recognition by TLR4/MD2, decreased ability to invade and persist in mammalian cells.
  
  
  CONCLUSIONS
  ESA_RS09200 in C. sakazakii BAA894 encodes a PEA transferase that specifically adds a PEA to the 4'-phosphate residue of lipid A, but not regulated by the PmrA-PmrB system. PEA modification of lipid A reduces recognition and killing by the host innate immune system.
  
  
  CONCLUSIONS
  This study showed that modification of the lipid A moiety of C. sakazakii with PEA increased resistance to CAMP and recognition of the immune response although signalling of TLR4/MD2 cascade, suggesting that the organism could not successfully evade the host innate immune system without the transference of PEA to its lipid A moiety.
authors: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.|School of Biotechnology, Jiangnan University, Wuxi, China.
authors: L
authors: L
authors: Liu
authors: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China. yanyanli1123@hotmail.com.|Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, China. yanyanli1123@hotmail.com.
authors: Y
authors: Y
authors: Li
authors: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China. xwang@jiangnan.edu.cn.|School of Biotechnology, Jiangnan University, Wuxi, China. xwang@jiangnan.edu.cn.|Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, China. xwang@jiangnan.edu.cn.
authors: X
authors: X
authors: Wang
authors: School of Biotechnology, Jiangnan University, Wuxi, China.
authors: W
authors: W
authors: Guo
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology; D018938:Caco-2 Cells; D044083:Cronobacter sakazakii / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D004982:Ethanolaminephosphotransferase / Q000235:genetics / Q000378:metabolism*; D004983:Ethanolamines / Q000378:metabolism; D006801:Humans; D008050:Lipid A / Q000737:chemistry / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism
chemical_list: D023181:Antimicrobial Cationic Peptides; D004983:Ethanolamines; D008050:Lipid A; D010710:Phosphates; C005448:phosphorylethanolamine; D004982:Ethanolaminephosphotransferase
keywords: 
  Cronobacter sakazakii
  ; EptA; lipid A; lipopolysaccharide; phosphoethanolamine transferase