Benaroudj N, Goldberg A L
Harvard Medical School, Department of Cell Biology, 240 Longwood Avenue, Boston, Massachusetts 02115, USA.
Nat Cell Biol. 2000 Nov;2(11):833-9. doi: 10.1038/35041081.
The proteasome-activating nucleotidase (PAN) from Methanococcus jannaschii is a complex of relative molecular mass 650,000 that is homologous to the ATPases in the eukaryotic 26S proteasome. When mixed with 20S archaeal proteasomes and ATP, PAN stimulates protein degradation. Here we show that PAN reduces aggregation of denatured proteins and enhances their refolding. These processes do not require ATP hydrolysis, although ATP binding enhances the ability of PAN to prevent aggregation. PAN also catalyses the unfolding of the green fluorescent protein with an 11-residue ssrA extension at its carboxy terminus (GFP11). This unfolding requires ATP hydrolysis, and is linked to GFP11 degradation when 20S proteasomes are also present. This unfolding activity seems to be essential for ATP-dependent proteolysis, although PAN may function by itself as a molecular chaperone.
詹氏甲烷球菌的蛋白酶体激活核苷酸酶（PAN）是一种相对分子质量为650,000的复合物，与真核生物26S蛋白酶体中的ATP酶同源。当与20S古细菌蛋白酶体和ATP混合时，PAN会刺激蛋白质降解。在此我们表明，PAN可减少变性蛋白质的聚集并增强其重折叠。这些过程不需要ATP水解，尽管ATP结合可增强PAN防止聚集的能力。PAN还催化羧基末端带有11个残基ssrA延伸的绿色荧光蛋白（GFP11）的解折叠。这种解折叠需要ATP水解，并且当也存在20S蛋白酶体时与GFP11降解相关。尽管PAN可能自身作为分子伴侣发挥作用，但这种解折叠活性似乎对于ATP依赖性蛋白水解至关重要。
