Functional characterization of the trigger factor protein PceT of tetrachloroethene-dechlorinating Desulfitobacterium hafniense Y51
Functional characterization of the trigger factor protein PceT of tetrachloroethene-dechlorinating Desulfitobacterium hafniense Y51
复制标题
四氯乙烯脱氯哈夫脱硫杆菌Y51触发因子蛋白PceT的功能表征
DOI：
10.1007/s00253-009-1958-z
复制
发表时间：
2009
影响因子：
5
通讯作者：
K. Furukawa
中科院分区：
文献类型：
--
作者：
Y. Morita;Taiki Futagami;M. Goto;K. Furukawa
哈氏脱硫杆菌Y51菌株在pceA编码的PceA还原脱卤酶的作用下，通过三氯乙烯将四氯乙烯脱氯为顺式-1，2-二氯乙烯(cis-DCE)。PceA基因与PCEB、PCEC和pceT构成一个基因簇。然而，除pceA外，基因的组成仍有待鉴定。在本研究中，我们描述了PceT的功能。Y51菌株的PceT与触发因子蛋白具有序列同源性，尽管它在进化上与大肠杆菌充分描述的触发因子蛋白相距甚远。用6x组氨酸标记的PceT蛋白在大肠杆菌中以可溶性形式表达。重组PceT融合蛋白对N-琥珀酰基-丙基-丙氨酸-苯丙基-对-硝基-对硝基苯胺显色肽具有多肽-丙基-顺-反异构酶活性。PceT融合蛋白对化学变性的柠檬酸合成酶也显示出伴侣活性。用抗PceA和PceT的抗体进行免疫沉淀分析表明，PceT通过N末端双精氨酸易位(TAT)信号序列与PceA的前体形式特异性结合。另一方面，PceT未能结合失去TAT信号序列的成熟形式的PceA。这是脱卤素呼吸菌中的第一份报告，表明PceT负责前体PceA的正确折叠。
Desulfitobacterium hafniense strain Y51 dechlorinates tetrachloroethene to cis-1,2-dichloroethene (cis-DCE) via trichloroethene by the action of the PceA reductive dehalogenase encoded by pceA. The pceA gene constitutes a gene cluster with pceB, pceC, and pceT. However, the gene components, except for pceA, still remained to be characterized. In the present study, we characterized the function of PceT. PceT of strain Y51 showed a sequence homology with trigger factor proteins, although it is evolutionally distant from the well-characterized trigger factor protein of Escherichia coli. The PceT protein tagged with 6x histidine was expressed as a soluble form in E. coli. The recombinant PceT fusion protein exhibited peptidyl-proryl cis–trans isomerase activity toward the chromogenic peptide N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide. The PceT fusion protein also exhibited chaperon activity towards the chemically denatured citrate synthase. Immunoprecipitation analysis using antibodies raised against PceA and PceT demonstrated that PceT specifically binds to the precursor form of PceA with an N-terminal twin-arginine translocation (TAT) signal sequence. On the other hand, PceT failed to bind the mature form of PceA that lost the TAT signal sequence. This is the first report in dehalorespiring bacteria, indicating that PceT is responsible for the correct folding of the precursor PceA.