Mendoza J A, Dulin P, Warren T
Department of Chemistry, California State University at San Marcos, San Marcos, California 92096-0001, U.S.A.
Cryobiology. 2000 Dec;41(4):319-23. doi: 10.1006/cryo.2000.2287.
The chaperonins GroEL and GroES were shown to facilitate the refolding of urea-unfolded rhodanese in an ATP-dependent process at 25 or 37 degrees C. A diminished chaperonin activity was observed at 10 degrees C, however. At low temperature, GroEL retains its ability to form a complex with urea-unfolded rhodanese or with GroES. GroEL is also able to bind ATP at 10 degrees C. Interestingly, the ATPase activity of GroEL was highly decreased at low temperatures. Hydrolysis of ATP by GroEL was 60% less at 10 degrees C than at 25 degrees C. We conclude that the reduced hydrolysis of ATP by GroEL is a major but perhaps not the only factor responsible for the diminished chaperonin activity at 10 degrees C. GroEL may function primarily at higher temperatures in which the ability of GroEL to hydrolyze ATP is not compromised.
伴侣蛋白GroEL和GroES已被证明在25或37摄氏度下，能通过依赖ATP的过程促进尿素变性的硫氰酸酶重折叠。然而，在10摄氏度时观察到伴侣蛋白活性降低。在低温下，GroEL保留了与尿素变性的硫氰酸酶或与GroES形成复合物的能力。GroEL在10摄氏度时也能够结合ATP。有趣的是，GroEL的ATP酶活性在低温下大幅降低。在10摄氏度时，GroEL水解ATP的量比在25摄氏度时少60%。我们得出结论，GroEL水解ATP减少是导致10摄氏度时伴侣蛋白活性降低的主要但可能不是唯一因素。GroEL可能主要在较高温度下起作用，在这些温度下GroEL水解ATP的能力不受影响。
