Plasmodium falciparum heat shock protein 70 is able to suppress the thermosensitivity of an Escherichia coli DnaK mutant strain
Plasmodium falciparum heat shock protein 70 is able to suppress the thermosensitivity of an Escherichia coli DnaK mutant strain
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DOI：
10.1007/s00438-005-1150-9
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发表时间：
2005-08-01
影响因子：
3.1
通讯作者：
Blatch, GL
中科院分区：
文献类型：
--
作者：
Shonhai, A;Boshoff, A;Blatch, GL
热休克蛋白70（Hsp 70）和热休克蛋白40（Hsp 40）是分子伴侣，确保细胞的蛋白质在正常和应激条件下正确折叠和发挥功能。已知恶性疟原虫在热应激反应中过量产生热休克蛋白70（PfHsp 70）;然而，该蛋白的体内功能仍需要探索。使用体内互补试验，我们发现PfHsp 70能够抑制大肠杆菌dnaK 756菌株的热敏性，但不能抑制相应的缺失菌株（Delta dnaK 52）或dnaK 103菌株，其产生截短的DnaK。构建了编码PfHsp 70的ATP酶结构域与大肠杆菌的底物结合结构域（SBD）融合的构建体。coli DnaK（简称PfK）的ATP酶结构域，以及E. coli DnaK与PfHsp 70（KPf）的SBD偶联。PfK不能抑制任何E.大肠杆菌菌株。相反，KPf能够抑制E. coli dnaK 756菌株。我们还确定了两个关键的氨基酸残基（V401和Q402）之间的ATP酶结构域和SBD的PfHsp 70的体内功能是必不可少的接头区域。这是第一个来自真核寄生虫的Hsp 70可以抑制原核系统中的热敏性的例子。此外，我们的研究结果还表明，结构域间的通信是至关重要的PfHsp 70和PfHsp 70-DnaK嵌合体的功能。我们讨论的影响，这些数据的作用机制的热休克蛋白70-热休克蛋白40分子伴侣机器。
Heat shock protein 70 (Hsp70) and heat shock protein 40 (Hsp40) are molecular chaperones that ensure that the proteins of the cell are properly folded and functional under both normal and stressful conditions. The malaria parasite Plasmodium falciparum is known to overproduce a heat shock protein 70 (PfHsp70) in response to thermal stress; however, the in vivo function of this protein still needs to be explored. Using in vivo complementation assays, we found that PfHsp70 was able to suppress the thermosensitivity of an Escherichia coli dnaK756 strain, but not that of the corresponding deletion strain (Delta dnaK52) or dnaK103 strain, which produces a truncated DnaK. Constructs were generated that encoded the ATPase domain of PfHsp70 fused to the substrate-binding domain (SBD) of E. coli DnaK (referred to as PfK), and the ATPase domain of E. coli DnaK coupled to the SBD of PfHsp70 (KPf). PfK was unable to suppress the thermosensitivity of any of the E. coli strains. In contrast, KPf was able to suppress the thermosensitivity in the E. coli dnaK756 strain. We also identified two key amino acid residues (V401 and Q402) in the linker region between the ATPase domain and SBD that are essential for the in vivo function of PfHsp70. This is the first example of an Hsp70 from a eukaryotic parasite that can suppress thermosensitivity in a prokaryotic system. In addition, our results also suggest that interdomain communication is critical for the function of the PfHsp70 and PfHsp70-DnaK chimeras. We discuss the implications of these data for the mechanism of action of the Hsp70-Hsp40 chaperone machinery.