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-Structure paper
タイトル | GroEL actively stimulates folding of the endogenous substrate protein PepQ. |
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ジャーナル・号・ページ | Nat Commun, Vol. 8, Page 15934, Year 2017 |
掲載日 | 2017年6月30日 |
著者 | Jeremy Weaver / Mengqiu Jiang / Andrew Roth / Jason Puchalla / Junjie Zhang / Hays S Rye / |
PubMed 要旨 | Many essential proteins cannot fold without help from chaperonins, like the GroELS system of Escherichia coli. How chaperonins accelerate protein folding remains controversial. Here we test key ...Many essential proteins cannot fold without help from chaperonins, like the GroELS system of Escherichia coli. How chaperonins accelerate protein folding remains controversial. Here we test key predictions of both passive and active models of GroELS-stimulated folding, using the endogenous E. coli metalloprotease PepQ. While GroELS increases the folding rate of PepQ by over 15-fold, we demonstrate that slow spontaneous folding of PepQ is not caused by aggregation. Fluorescence measurements suggest that, when folding inside the GroEL-GroES cavity, PepQ populates conformations not observed during spontaneous folding in free solution. Using cryo-electron microscopy, we show that the GroEL C-termini make physical contact with the PepQ folding intermediate and help retain it deep within the GroEL cavity, resulting in reduced compactness of the PepQ monomer. Our findings strongly support an active model of chaperonin-mediated protein folding, where partial unfolding of misfolded intermediates plays a key role. |
リンク | Nat Commun / PubMed:28665408 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 7.9 - 8.3 Å |
構造データ | EMDB-8316: EMDB-8317: EMDB-8318: EMDB-8319: |
由来 |
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