期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 105, 期 45, 页码 17351-17355出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.0809794105
关键词
cis folding; GroEL; maltose-binding protein; Rubisco
资金
- Howard Hughes Medical Institute
The original experiments reconstituting GroEL-GroES-mediated protein folding were carried out under nonpermissive conditions, where the chaperonin system was absolutely required and substrate proteins could not achieve the native state if diluted directly from denaturant into solution. Under permissive conditions, however, employing lower substrate concentration and lower temperature, some substrate proteins can be refolded both by the chaperonin system and while free in solution. For several of these, the protein refolds more rapidly inside the GroEL-GroES cis chamber than free in solution, suggesting that the chamber may have an active role in assisting protein folding. Here, we observe that the difference is caused by reversible multimolecular association while folding in solution, an avenue of kinetic partitioning that slows the overall rate of renaturation relative to the chaperonin chamber, where such associations cannot occur. For Rubisco, reversible aggregation during folding in solution was observed by gel filtration, For a mutant of maltose-binding protein (DM-MBP), the rate of folding in solution declined with increasing concentration, and the folding reaction produced light scattering. Under solution conditions where chloride was absent, however, light scattering no longer occurred, and DM-MBP folded at the same rate as in the cis cavity. In a further test, dihydrofolate reductase, thermally inactivated in the cis cavity or in solution, was substantially reactivated upon temperature downshift in the cis cavity but not in solution, where aggregation occurred. We conclude that the GroEL-GroES chamber behaves as a passive Anfinsen cage whose primary role is to prevent multimolecular association during folding.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据