低温下氧化伴侣蛋白 GroEL 与未折叠蛋白的相互作用。

Interaction of oxidized chaperonin GroEL with an unfolded protein at low temperatures.

机构信息

Department of Biology and Molecular Biology Institute, San Diego State University, San Diego, CA 92182-4614, USA.

出版信息

Biosci Rep. 2012 Jun;32(3):299-303. doi: 10.1042/BSR20110104.

DOI:10.1042/BSR20110104

Abstract

The chaperonin GroEL binds to non-native substrate proteins via hydrophobic interactions, preventing their aggregation, which is minimized at low temperatures. In the present study, we investigated the refolding of urea-denatured rhodanese at low temperatures, in the presence of ox-GroEL (oxidized GroEL), which contains increased exposed hydrophobic surfaces and retains its ability to hydrolyse ATP. We found that ox-GroEL could efficiently bind the urea-unfolded rhodanese at 4°C, without requiring excess amount of chaperonin relative to normal GroEL (i.e. non-oxidized). The release/reactivation of rhodanese from GroEL was minimal at 4°C, but was found to be optimal between 22 and 37°C. It was found that the loss of the ATPase activity of ox-GroEL at 4°C prevented the release of rhodanese from the GroEL-rhodanese complex. Thus ox-GroEL has the potential to efficiently trap recombinant or non-native proteins at 4°C and release them at higher temperatures under appropriate conditions.

摘要

伴侣蛋白 GroEL 通过疏水相互作用与非天然底物蛋白结合，防止其聚集，在低温下聚集程度最小。在本研究中，我们研究了在存在氧化型 GroEL（氧化 GroEL）的情况下，尿素变性的 rhodanese 在低温下的重折叠，氧化型 GroEL 含有增加的暴露疏水表面，并保持其水解 ATP 的能力。我们发现氧化型 GroEL 可以在 4°C 下有效地结合尿素变性的 rhodanese，而不需要相对于正常 GroEL（即非氧化型）过量的伴侣蛋白。在 4°C 时，rhodanese 从 GroEL 中的释放/再激活最小，但在 22 至 37°C 之间发现是最佳的。结果发现，氧化型 GroEL 在 4°C 时 ATPase 活性的丧失阻止了 rhodanese 从 GroEL-rhodanese 复合物中的释放。因此，氧化型 GroEL 有可能在 4°C 时有效地捕获重组或非天然蛋白质，并在适当的条件下在较高温度下释放它们。