Rommelaere H, De Neve M, Melki R, Vandekerckhove J, Ampe C
Flanders Interuniversity Institute for Biotechnology (VIB), Department of Biochemistry, Faculty of Medicine, University Ghent, Belgium.
Biochemistry. 1999 Mar 16;38(11):3246-57. doi: 10.1021/bi9815905.
The nonhomologous proteins actin and alpha- and beta-tubulin need the assistance of the cytosolic chaperonin containing TCP-1 (CCT) to reach their correct native state, and their folding requires a transient binary complex formation with CCT. We show that separate or combined deletion of three delineated hydrophobic sequences in actin disturbs the interaction with CCT. These sites are situated between residues 125-179, 244-285, and 340-375. Also, alpha- and beta-tubulin contain at least one recognition region, and intriguingly, it has a similar distribution of hydrophobic residues as region 244-285 in actin. Internal deletion of the sites in actin favor a model for cooperative binding of target proteins to CCT. Peptide mimetics, representing the binding regions, inhibit target polypeptide binding to CCT, suggesting that actin and tubulin contact similar CCT subunits. In addition, we show that actin recognition by class II chaperonins is different from that by class I.
非同源蛋白肌动蛋白以及α-和β-微管蛋白需要包含TCP-1的胞质伴侣蛋白（CCT）的协助才能达到其正确的天然状态，并且它们的折叠需要与CCT形成瞬时二元复合物。我们发现，肌动蛋白中三个划定的疏水序列的单独或组合缺失会扰乱与CCT的相互作用。这些位点位于第125 - 179、244 - 285和340 - 375位残基之间。此外，α-和β-微管蛋白至少包含一个识别区域，有趣的是，其疏水残基的分布与肌动蛋白中244 - 285区域相似。肌动蛋白中这些位点的内部缺失支持了靶蛋白与CCT协同结合的模型。代表结合区域的肽模拟物抑制靶多肽与CCT的结合，这表明肌动蛋白和微管蛋白与相似的CCT亚基接触。此外，我们表明II类伴侣蛋白对肌动蛋白的识别与I类不同。
