Okochi Mina, Matsuzaki Hiroki, Nomura Tomoko, Ishii Noriyuki, Yohda Masafumi
Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.
Extremophiles. 2005 Apr;9(2):127-34. doi: 10.1007/s00792-004-0427-y. Epub 2004 Nov 9.
The group II chaperonin from the hyperthermophilic archaeum Pyrococcus horikoshii OT3 (PhCPN) and its functional cooperation with the cognate prefoldin were investigated. PhCPN existed as a homo-oligomer in a double-ring structure, which protected the citrate synthase of a porcine heart from thermal aggregation at 45 degrees C, and did the same on the isopropylmalate dehydrogenase (IPMDH) of a thermophilic bacterium, Thermus thermophilus HB8, at 90 degrees C. PhCPN also enhanced the refolding of green fluorescent protein (GFP), which had been unfolded by low pH, in an ATP-dependent manner. Unexpectedly, functional cooperation between PhCPN and Pyrococcus prefoldin (PhPFD) in the refolding of GFP was not observed. Instead, cooperation between PhCPN and PhPFD was observed in the refolding of IPMDH unfolded with guanidine hydrochloride. Although PhCPN alone was not effective in the refolding of IPMDH, the refolding efficiency was enhanced by the cooperation of PhCPN with PhPFD.
对嗜热古菌火球菌OT3（PhCPN）的II型伴侣蛋白及其与同源预折叠蛋白的功能协同作用进行了研究。PhCPN以双环结构的同型寡聚体形式存在，它在45℃时保护猪心脏的柠檬酸合酶免受热聚集，在90℃时对嗜热栖热菌HB8的异丙基苹果酸脱氢酶（IPMDH）也有同样的保护作用。PhCPN还以ATP依赖的方式增强了因低pH而展开的绿色荧光蛋白（GFP）的重折叠。出乎意料的是，未观察到PhCPN与火球菌预折叠蛋白（PhPFD）在GFP重折叠过程中的功能协同作用。相反，在盐酸胍展开的IPMDH的重折叠过程中观察到了PhCPN与PhPFD之间的协同作用。虽然单独的PhCPN对IPMDH的重折叠无效，但PhCPN与PhPFD的协同作用提高了重折叠效率。
