Specificity of the lipase-specific foldases of gram-negative bacteria and the role of the membrane anchor
Specificity of the lipase-specific foldases of gram-negative bacteria and the role of the membrane anchor
复制标题
革兰氏阴性菌脂肪酶特异性折叠酶的特异性和膜锚的作用
DOI：
10.1007/s004380050020
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
J. Tommassen
中科院分区：
文献类型：
--
作者：
M. El Khattabi;C. Ockhuijsen;W. Bitter;K. Jaeger;J. Tommassen
假单胞菌和其他革兰氏阴性菌通过II型分泌途径分泌的脂肪酶的折叠是由专用的伴侣蛋白促进的，称为脂肪酶特异性折叠酶（Lifs）。Lifs是膜锚定蛋白，具有大的质周结构域。Lif与其同源脂肪酶之间的功能相互作用是特异性的，因为铜绿假单胞菌Lif被发现不能替代来自伯克霍尔德菌的Lif或钙酸不动杆菌的Lif。然而，P. aeruginosa Lif能够激活来自近亲P. alcaligenes的脂肪酶。由铜绿假单胞菌和B. glumae Lifs部分构建的杂交蛋白表明，B. glumae Lifs的c端138个氨基酸决定了与同源脂肪酶相互作用的特异性。此外，当在具有可切割信号序列的框架中克隆时，B. glumae Lif的质周结构域具有功能，这表明膜锚点在体内并不是Lif功能所必需的。而重组的Lif被释放到培养基中，说明膜锚的作用是阻止Lif与脂肪酶一起分泌。
Abstract Folding of lipases that are secreted by Pseudomonads and other gram-negative bacteria via the type II secretion pathway is facilitated by dedicated chaperones, called lipase-specific foldases (Lifs). Lifs are membrane-anchored proteins with a large periplasmic domain. The functional interaction between the Lif and its cognate lipase is specific, since the Pseudomonas aeruginosa Lif was found not to substitute for Lifs from Burkholderia glumae or Acinetobacter calcoaceticus. However, the P. aeruginosa Lif was able to activate the lipase from the closely related species P. alcaligenes. Hybrid proteins constructed from parts of the P. aeruginosa and B. glumae Lifs revealed that the C-terminal 138 amino acids of the B. glumae Lif determine the specificity of the interaction with the cognate lipase. Furthermore, the periplasmic domain of the B. glumae Lif was functional when cloned in frame with a cleavable signal sequence, which demonstrates that the membrane anchor is not essential for Lif function in vivo. However, the recombinant Lif was released into the medium, indicating that the function of the membrane anchor is to prevent secretion of the Lif together with the lipase.