Zolkiewski M, Kessel M, Ginsburg A, Maurizi M R
Department of Biochemistry, Kansas State University, Manhattan 66506, USA.
Protein Sci. 1999 Sep;8(9):1899-903. doi: 10.1110/ps.8.9.1899.
Self-association of ClpB (a mixture of 95- and 80-kDa subunits) has been studied with gel filtration chromatography, analytical ultracentrifugation, and electron microscopy. Monomeric ClpB predominates at low protein concentration (0.07 mg/mL), while an oligomeric form is highly populated at >4 mg/mL. The oligomer formation is enhanced in the presence of 2 mM ATP or adenosine 5'-O-thiotriphosphate (ATPgammaS). In contrast, 2 mM ADP inhibits full oligomerization of ClpB. The apparent size of the ATP- or ATPgammaS-induced oligomer, as determined by gel filtration, sedimentation velocity and electron microscopy image averaging, and the molecular weight, as determined by sedimentation equilibrium, are consistent with those of a ClpB hexamer. These results indicate that the oligomerization reactions of ClpB are similar to those of other Hsp100 proteins.
已通过凝胶过滤色谱法、分析超速离心法和电子显微镜对ClpB（95 kDa和80 kDa亚基的混合物）的自缔合进行了研究。在低蛋白浓度（0.07 mg/mL）下，单体ClpB占主导，而在>4 mg/mL时，高度聚集形成寡聚体形式。在2 mM ATP或腺苷5'-O-硫代三磷酸（ATPγS）存在下，寡聚体形成增强。相反，2 mM ADP抑制ClpB的完全寡聚化。通过凝胶过滤、沉降速度和电子显微镜图像平均确定的ATP或ATPγS诱导的寡聚体的表观大小，以及通过沉降平衡确定的分子量，与ClpB六聚体的大小一致。这些结果表明，ClpB的寡聚化反应与其他Hsp100蛋白的寡聚化反应相似。
