Subunit asymmetry and roles of conformational switching in the hexameric AAA+ ring of ClpX
The hexameric AAA+ ring of Escherichia coli ClpX, an ATP-dependent machine for protein unfolding and translocation, functions with the ClpP peptidase to degrade target substrates. For efficient function, ClpX subunits must switch between nucleotide-loadable (L) and nucleotide-unloadable (U) conforma...
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| Format: | Article |
| Language: | en_US |
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Nature Publishing Group
2017
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| Online Access: | http://hdl.handle.net/1721.1/108783 https://orcid.org/0000-0002-7390-3580 https://orcid.org/0000-0002-9309-8662 https://orcid.org/0000-0002-1719-5399 |
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| author | Stinson, Benjamin Michael Baytshtok, Vladimir Schmitz, Karl Robert Baker, Tania Sauer, Robert T. |
| author2 | Massachusetts Institute of Technology. Department of Biology |
| author_facet | Massachusetts Institute of Technology. Department of Biology Stinson, Benjamin Michael Baytshtok, Vladimir Schmitz, Karl Robert Baker, Tania Sauer, Robert T. |
| author_sort | Stinson, Benjamin Michael |
| collection | MIT |
| description | The hexameric AAA+ ring of Escherichia coli ClpX, an ATP-dependent machine for protein unfolding and translocation, functions with the ClpP peptidase to degrade target substrates. For efficient function, ClpX subunits must switch between nucleotide-loadable (L) and nucleotide-unloadable (U) conformations, but the roles of switching are uncertain. Moreover, it is controversial whether working AAA+-ring enzymes assume symmetric or asymmetric conformations. Here, we show that a covalent ClpX ring with one subunit locked in the U conformation catalyzes robust ATP hydrolysis, with each unlocked subunit able to bind and hydrolyze ATP, albeit with highly asymmetric position-specific affinities. Preventing U↔L interconversion in one subunit alters the cooperativity of ATP hydrolysis and reduces the efficiency of substrate binding, unfolding and degradation, showing that conformational switching enhances multiple aspects of wild-type ClpX function. These results support an asymmetric and probabilistic model of AAA+-ring activity. |
| first_indexed | 2024-09-23T12:43:57Z |
| format | Article |
| id | mit-1721.1/108783 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T12:43:57Z |
| publishDate | 2017 |
| publisher | Nature Publishing Group |
| record_format | dspace |
| spelling | mit-1721.1/1087832022-09-28T09:45:42Z Subunit asymmetry and roles of conformational switching in the hexameric AAA+ ring of ClpX Stinson, Benjamin Michael Baytshtok, Vladimir Schmitz, Karl Robert Baker, Tania Sauer, Robert T. Massachusetts Institute of Technology. Department of Biology Whitehead Institute for Biomedical Research Stinson, Benjamin Michael Baytshtok, Vladimir Schmitz, Karl Robert Baker, Tania Sauer, Robert T. The hexameric AAA+ ring of Escherichia coli ClpX, an ATP-dependent machine for protein unfolding and translocation, functions with the ClpP peptidase to degrade target substrates. For efficient function, ClpX subunits must switch between nucleotide-loadable (L) and nucleotide-unloadable (U) conformations, but the roles of switching are uncertain. Moreover, it is controversial whether working AAA+-ring enzymes assume symmetric or asymmetric conformations. Here, we show that a covalent ClpX ring with one subunit locked in the U conformation catalyzes robust ATP hydrolysis, with each unlocked subunit able to bind and hydrolyze ATP, albeit with highly asymmetric position-specific affinities. Preventing U↔L interconversion in one subunit alters the cooperativity of ATP hydrolysis and reduces the efficiency of substrate binding, unfolding and degradation, showing that conformational switching enhances multiple aspects of wild-type ClpX function. These results support an asymmetric and probabilistic model of AAA+-ring activity. National Institutes of Health (U.S.) (Grant GM-101988) Massachusetts Institute of Technology (Poitras Predoctoral Fellowship) 2017-05-09T17:38:42Z 2017-05-09T17:38:42Z 2015-04 2015-01 Article http://purl.org/eprint/type/JournalArticle 1545-9993 1545-9985 http://hdl.handle.net/1721.1/108783 Stinson, Benjamin M et al. “Subunit Asymmetry and Roles of Conformational Switching in the Hexameric AAA+ Ring of ClpX.” Nature Structural & Molecular Biology (2015): n. pag. https://orcid.org/0000-0002-7390-3580 https://orcid.org/0000-0002-9309-8662 https://orcid.org/0000-0002-1719-5399 en_US http://dx.doi.org/10.1038/nsmb.3012 Nature Structural & Molecular Biology Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Nature Publishing Group PMC |
| spellingShingle | Stinson, Benjamin Michael Baytshtok, Vladimir Schmitz, Karl Robert Baker, Tania Sauer, Robert T. Subunit asymmetry and roles of conformational switching in the hexameric AAA+ ring of ClpX |
| title | Subunit asymmetry and roles of conformational switching in the hexameric AAA+ ring of ClpX |
| title_full | Subunit asymmetry and roles of conformational switching in the hexameric AAA+ ring of ClpX |
| title_fullStr | Subunit asymmetry and roles of conformational switching in the hexameric AAA+ ring of ClpX |
| title_full_unstemmed | Subunit asymmetry and roles of conformational switching in the hexameric AAA+ ring of ClpX |
| title_short | Subunit asymmetry and roles of conformational switching in the hexameric AAA+ ring of ClpX |
| title_sort | subunit asymmetry and roles of conformational switching in the hexameric aaa ring of clpx |
| url | http://hdl.handle.net/1721.1/108783 https://orcid.org/0000-0002-7390-3580 https://orcid.org/0000-0002-9309-8662 https://orcid.org/0000-0002-1719-5399 |
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