The Pseudomonas aeruginosa lipid A deacylase:: Selection for expression and loss within the cystic fibrosis airway
The Pseudomonas aeruginosa lipid A deacylase:: Selection for expression and loss within the cystic fibrosis airway
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DOI：
10.1128/jb.188.1.191-201.2006
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发表时间：
2006-01-01
影响因子：
3.2
通讯作者：
Miller, SI
中科院分区：
文献类型：
--
作者：
Ernst, RK;Adams, KN;Miller, SI
脂多糖（LPS）是革兰氏阴性菌的主要表面组分，并且LPS的组分脂质A通过Toll样受体4/MD-2复合物被先天免疫系统识别。铜绿假单胞菌是一种环境革兰氏阴性菌，可机会性感染囊性纤维化（CF）患者的呼吸道，可合成各种结构的脂质A。来自从患有CF的婴儿分离的铜绿假单胞菌菌株的脂质A具有特定结构，其包括3位3-OH C10脂肪酸的去除。在这里，我们证明了与环境分离株相比，CF婴儿分离株中铜绿假单胞菌脂质A3-O-脱酰酶（PagL）的表达增加。PagL活性在环境分离株中通过在限制镁的培养基中生长而增加，在实验室适应的铜绿假单胞菌菌株中通过在低温下生长而降低。等密度梯度离心法证明铜绿假单胞菌PagL是一种外膜蛋白。铜绿假单胞菌pagL在鼠伤寒沙门氏菌和大肠杆菌中的异源表达导致3-OH C14脂肪酸从脂质A中去除，表明铜绿假单胞菌PagL识别3-OH C10或3-OH C14。最后，在来自患有严重肺病的患者的一些临床铜绿假单胞菌分离株中未观察到脱酰脂质A物质，这表明在对CF气道的长期适应期间可能发生PagL功能丧失。
Lipopolysaccharide (LPS) is the major surface component of gram-negative bacteria, and a component of LPS, lipid A, is recognized by the innate immune system through the Toll-like receptor 4/MD-2 complex. Pseudomonas aeruginosa, an environmental gram-negative bacterium that opportunistically infects the respiratory tracts of patients with cystic fibrosis (CF), can synthesize various structures of lipid A. Lipid A from P. aeruginosa strains isolated from infants with CF has a specific structure that includes the removal of the 3 position 3-OH C10 fatty acid. Here we demonstrate increased expression of the P. aeruginosa lipid A 3-O-deacylase (PagL) in isolates from CF infants compared to that in environmental isolates. PagL activity was increased in environmental isolates by growth in medium limited for magnesium and decreased by growth at low temperature in laboratory-adapted strains of P. aeruginosa. P. aeruginosa PagL was shown to be an outer membrane protein by isopycnic density gradient centrifugation. Heterologous expression of P. aeruginosa pagL in Salmonella enterica serovar Typhimurium and Escherichia coli resulted in removal of the 3-OH C14 fatty acid from lipid A, indicating that P. aeruginosa PagL recognizes either 3-OH C10 or 3-OH C14. Finally, deacylated lipid A species were not observed in some clinical P. aeruginosa isolates from patients with severe pulmonary disease, suggesting that loss of PagL function can occur during long-term adaptation to the CF airway.