Structural basis of ClpXP recognition and unfolding of ssrA-tagged substrates
When ribosomes fail to complete normal translation, all cells have mechanisms to ensure degradation of the resulting partial proteins to safeguard proteome integrity. In Escherichia coli and other eubacteria, the tmRNA system rescues stalled ribosomes and adds an ssrA tag or degron to the C-terminus...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
eLife Sciences Publications Ltd
2020-10-01
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| Series: | eLife |
| Subjects: | |
| Online Access: | https://elifesciences.org/articles/61496 |
| _version_ | 1811252888453775360 |
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| author | Xue Fei Tristan A Bell Sarah R Barkow Tania A Baker Robert T Sauer |
| author_facet | Xue Fei Tristan A Bell Sarah R Barkow Tania A Baker Robert T Sauer |
| author_sort | Xue Fei |
| collection | DOAJ |
| description | When ribosomes fail to complete normal translation, all cells have mechanisms to ensure degradation of the resulting partial proteins to safeguard proteome integrity. In Escherichia coli and other eubacteria, the tmRNA system rescues stalled ribosomes and adds an ssrA tag or degron to the C-terminus of the incomplete protein, which directs degradation by the AAA+ ClpXP protease. Here, we present cryo-EM structures of ClpXP bound to the ssrA degron. C-terminal residues of the ssrA degron initially bind in the top of an otherwise closed ClpX axial channel and subsequently move deeper into an open channel. For short-degron protein substrates, we show that unfolding can occur directly from the initial closed-channel complex. For longer degron substrates, our studies illuminate how ClpXP transitions from specific recognition into a nonspecific unfolding and translocation machine. Many AAA+ proteases and protein-remodeling motors are likely to employ similar multistep recognition and engagement strategies. |
| first_indexed | 2024-04-12T16:42:19Z |
| format | Article |
| id | doaj.art-623a65ede5f24ec0a7f8e65a342d62ab |
| institution | Directory Open Access Journal |
| issn | 2050-084X |
| language | English |
| last_indexed | 2024-04-12T16:42:19Z |
| publishDate | 2020-10-01 |
| publisher | eLife Sciences Publications Ltd |
| record_format | Article |
| series | eLife |
| spelling | doaj.art-623a65ede5f24ec0a7f8e65a342d62ab2022-12-22T03:24:44ZengeLife Sciences Publications LtdeLife2050-084X2020-10-01910.7554/eLife.61496Structural basis of ClpXP recognition and unfolding of ssrA-tagged substratesXue Fei0Tristan A Bell1Sarah R Barkow2Tania A Baker3https://orcid.org/0000-0002-0737-3411Robert T Sauer4https://orcid.org/0000-0002-1719-5399Departments of Biology, Massachusetts Institute of Technology, Cambridge, United StatesDepartments of Biology, Massachusetts Institute of Technology, Cambridge, United StatesChemistry, Massachusetts Institute of Technology, Cambridge, United StatesDepartments of Biology, Massachusetts Institute of Technology, Cambridge, United StatesDepartments of Biology, Massachusetts Institute of Technology, Cambridge, United StatesWhen ribosomes fail to complete normal translation, all cells have mechanisms to ensure degradation of the resulting partial proteins to safeguard proteome integrity. In Escherichia coli and other eubacteria, the tmRNA system rescues stalled ribosomes and adds an ssrA tag or degron to the C-terminus of the incomplete protein, which directs degradation by the AAA+ ClpXP protease. Here, we present cryo-EM structures of ClpXP bound to the ssrA degron. C-terminal residues of the ssrA degron initially bind in the top of an otherwise closed ClpX axial channel and subsequently move deeper into an open channel. For short-degron protein substrates, we show that unfolding can occur directly from the initial closed-channel complex. For longer degron substrates, our studies illuminate how ClpXP transitions from specific recognition into a nonspecific unfolding and translocation machine. Many AAA+ proteases and protein-remodeling motors are likely to employ similar multistep recognition and engagement strategies.https://elifesciences.org/articles/61496AAA+ proteasecryo-EM structurestmRNA taggingdegradation specificityrecognition complexintermediate complex |
| spellingShingle | Xue Fei Tristan A Bell Sarah R Barkow Tania A Baker Robert T Sauer Structural basis of ClpXP recognition and unfolding of ssrA-tagged substrates eLife AAA+ protease cryo-EM structures tmRNA tagging degradation specificity recognition complex intermediate complex |
| title | Structural basis of ClpXP recognition and unfolding of ssrA-tagged substrates |
| title_full | Structural basis of ClpXP recognition and unfolding of ssrA-tagged substrates |
| title_fullStr | Structural basis of ClpXP recognition and unfolding of ssrA-tagged substrates |
| title_full_unstemmed | Structural basis of ClpXP recognition and unfolding of ssrA-tagged substrates |
| title_short | Structural basis of ClpXP recognition and unfolding of ssrA-tagged substrates |
| title_sort | structural basis of clpxp recognition and unfolding of ssra tagged substrates |
| topic | AAA+ protease cryo-EM structures tmRNA tagging degradation specificity recognition complex intermediate complex |
| url | https://elifesciences.org/articles/61496 |
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