Bioengineering Laboratory, RIKEN Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Biochem Biophys Res Commun. 2010 Jan 1;391(1):467-70. doi: 10.1016/j.bbrc.2009.11.081. Epub 2009 Nov 15.
Prefoldin is a molecular chaperone that captures a protein-folding intermediate and transfers it to a group II chaperonin for correct folding. Previous studies of archaeal prefoldins have shown that prefoldin only possesses holdase activity and is unable to fold unfolded proteins by itself. In this study, we have demonstrated for the first time that a prefoldin from hyperthermophilic archaeon, Pyrococcus horikoshii OT3 (PhPFD), exhibits refolding activity for denatured lysozyme at temperatures relatively lower than physiologically active temperatures. The interaction between PhPFD and denatured lysozyme was investigated by use of a surface plasmon resonance sensor at various temperatures. Although PhPFD showed strong affinity for denatured lysozyme at high temperature, it exhibited relatively weak interactions at lower temperature. The protein-folding seems to occur through binding and release from PhPFD by virtue of the weak affinity. Our results also imply that prefoldin might be able to contribute to the folding of some cellular proteins whose affinity with prefoldin is weak.
原核生物伴侣素是一种分子伴侣，它能捕获蛋白质折叠的中间产物，并将其转移到一个 II 型分子伴侣中进行正确折叠。以前对古菌原核生物伴侣素的研究表明，原核生物伴侣素只具有持留酶活性，不能独立折叠未折叠的蛋白质。在这项研究中，我们首次证明了来自嗜热古菌 Pyrococcus horikoshii OT3（PhPFD）的原核生物伴侣素具有在相对低于生理活性温度下使变性溶菌酶复性的活性。我们在不同温度下使用表面等离子体共振传感器研究了 PhPFD 与变性溶菌酶之间的相互作用。尽管 PhPFD 在高温下对变性溶菌酶表现出很强的亲和力，但在较低温度下表现出相对较弱的相互作用。这种蛋白质折叠似乎是通过 PhPFD 的弱亲和力的结合和释放来实现的。我们的结果还表明，原核生物伴侣素可能有助于折叠一些与原核生物伴侣素亲和力较弱的细胞蛋白质。
