PDF(Pubmed)
Abstract：
The Escherichia coli GroEL/ES chaperonin system facilitates protein folding in an ATP-driven manner. There are <100 obligate clients of this system in E. coli although GroEL can interact and assist the folding of a multitude of proteins in vitro. It has remained unclear, however, which features distinguish obligate clients from all the other proteins in an E. coli cell. To address this question, we established a system for selecting mutations in mouse dihydrofolate reductase (mDHFR), a GroEL interactor, that diminish its dependence on GroEL for folding. Strikingly, both synonymous and non-synonymous codon substitutions were found to reduce mDHFR\'s dependence on GroEL. The non-synonymous substitutions increase the rate of spontaneous folding whereas computational analysis indicates that the synonymous substitutions appear to affect translation rates at specific sites.
摘要：
大肠杆菌GroEL/ES分子伴侣系统以ATP驱动的方式促进蛋白质折叠。尽管GroEL可以在体外相互作用并帮助多种蛋白质的折叠,但在大肠杆菌中存在<100个该系统的专性客户。目前还不清楚,然而,这些特征将专性客户与大肠杆菌细胞中的所有其他蛋白质区分开来。为了解决这个问题，我们建立了一个选择小鼠二氢叶酸还原酶（mDHFR）突变的系统，GroEL交互器，这减少了它对GroEL折叠的依赖。引人注目的是，发现同义和非同义密码子替换均可降低mDHFR对GroEL的依赖性。非同义取代增加自发折叠的速率,而计算分析表明同义取代似乎影响特定位点的翻译速率。
