Thermodynamic Characterization of the Interaction between Prefoldin and Group II Chaperonin
Thermodynamic Characterization of the Interaction between Prefoldin and Group II Chaperonin
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DOI：
10.1016/j.jmb.2010.04.046
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发表时间：
2010-06-18
影响因子：
5.6
通讯作者：
Yohda, Masafumi
中科院分区：
文献类型：
--
作者：
Sahlan, Muhamad;Zako, Tamotsu;Yohda, Masafumi
前折叠蛋白（Prefoldin，PFD）是一种六聚体分子伴侣，可捕获蛋白质底物并将其转移至II组分子伴侣（CPN）以完成蛋白质折叠。我们利用嗜热古菌Thermococcus KS-1（T. KS-1）。在本研究中，我们确定了T。KS-1 PFD β 2亚基的表达，并对T. KS-1 CPN（CPN α和CPN β）和T. KS-1 PFD（PFD α 1-β 1和PFD α 2-β 2）。如从其氨基酸序列预测的，PFD β 2亚基符合与PFD β 1亚基和Pyrococcus horikoshii OT 3 PFD β亚基相似的结构，除了卷曲螺旋结构域的尖端，其被认为是CPN相互作用位点。T.使用Biacore T100系统在20至45 ℃的各种温度下分析KS-1 CPN和PFD（CPN α和PFD α 1-β 1; CPNa和PFD α 2-β 2; CPN β和PFD α 1-β 1;以及CPN β和PFD α 2-β 2）。PFDs和CPNs之间的亲和力随着温度的升高而增加。由缔合常数计算的热力学参数表明，PFD与CPN之间的相互作用是熵驱动的。在PFD CPN相互作用的四种组合中，CPN β和PFD α 2-β 2之间结合的熵差最大，并且亲和力在较高温度下显著增加。考虑到PFD α 2-β 2和CPN β亚基的表达在热休克时被诱导，我们的结果表明PFD α 1-β 1是T. KS-1 CPN，而PFD α 2-β 2对CPN β具有特异性。(C)2010爱思唯尔有限公司版权所有。
Prefoldin (PFD) is a hexameric chaperone that captures a protein substrate and transfers it to a group II chaperonin (CPN) to complete protein folding. We have studied the interaction between PFD and CPN using those from a hyperthermophilic archaeon, Thermococcus strain KS-1 (T. KS-1). In this study, we determined the crystal structure of the T. KS-1 PFD beta 2 subunit and characterized the interactions between T. KS-1 CPNs (CPN alpha and CPN beta) and T. KS-1 PFDs (PFD alpha 1-beta 1 and PFD alpha 2-beta 2). As predicted from its amino acid sequence, the PFD beta 2 subunit conforms to a structure similar to those of the PFD beta 1 subunit and the Pyrococcus horikoshii OT3 PFD beta subunit, with the exception of the tip of its coiled-coil domain, which is thought to be the CPN interaction site. The interactions between T. KS-1 CPNs and PFDs (CPN alpha and PFD alpha 1-beta 1; CPNa and PFD alpha 2-beta 2; CPN beta and PFD alpha 1-beta 1; and CPN beta and PFD alpha 2-beta 2) were analyzed using the Biacore T100 system at various temperatures ranging from 20 to 45 degrees C. The affinities between PFDs and CPNs increased with an increase in temperature. The thermodynamicparameters calculated from association constants showed that the interaction between PFD and CPN is entropy driven. Among the four combinations of PFD CPN interactions, the entropy difference in binding between CPN beta and PFD alpha 2-beta 2 was the largest, and affinity significantly increased at higher temperatures. Considering that expression of PFD alpha 2-beta 2 and CPN beta subunit is induced upon heat shock, our results suggest that PFD alpha 1-beta 1 is a general PFD for T. KS-1 CPNs, whereas PFD alpha 2-beta 2 is specific for CPN beta. (C) 2010 Elsevier Ltd. All rights reserved.