Structures of benzylsuccinate synthase elucidate roles of accessory subunits in glycyl radical enzyme activation and activity
Anaerobic degradation of the environmental pollutant toluene is initiated by the glycyl radical enzyme benzylsuccinate synthase (BSS), which catalyzes the radical addition of toluene to fumarate, forming benzylsuccinate. We have determined crystal structures of the catalytic α-subunit of BSS with it...
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| Format: | Article |
| Language: | en_US |
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National Academy of Sciences (U.S.)
2015
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| Online Access: | http://hdl.handle.net/1721.1/93788 https://orcid.org/0000-0001-5486-2755 |
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| author | Funk, Michael Andrew Judd, Evan T. Marsh, E. Neil G. Elliott, Sean J. Drennan, Catherine L |
| author2 | Massachusetts Institute of Technology. Department of Biology |
| author_facet | Massachusetts Institute of Technology. Department of Biology Funk, Michael Andrew Judd, Evan T. Marsh, E. Neil G. Elliott, Sean J. Drennan, Catherine L |
| author_sort | Funk, Michael Andrew |
| collection | MIT |
| description | Anaerobic degradation of the environmental pollutant toluene is initiated by the glycyl radical enzyme benzylsuccinate synthase (BSS), which catalyzes the radical addition of toluene to fumarate, forming benzylsuccinate. We have determined crystal structures of the catalytic α-subunit of BSS with its accessory subunits β and γ, which both bind a [4Fe-4S] cluster and are essential for BSS activity in vivo. We find that BSSα has the common glycyl radical enzyme fold, a 10-stranded β/α-barrel that surrounds the glycyl radical cofactor and active site. Both accessory subunits β and γ display folds related to high potential iron–sulfur proteins but differ substantially from each other in how they interact with the α-subunit. BSSγ binds distally to the active site, burying a hydrophobic region of BSSα, whereas BSSβ binds to a hydrophilic surface of BSSα that is proximal to the active site. To further investigate the function of BSSβ, we determined the structure of a BSSαγ complex. Remarkably, we find that the barrel partially opens, allowing the C-terminal region of BSSα that houses the glycyl radical to shift within the barrel toward an exit pathway. The structural changes that we observe in the BSSαγ complex center around the crucial glycyl radical domain, thus suggesting a role for BSSβ in modulating the conformational dynamics required for enzyme activity. Accompanying proteolysis experiments support these structural observations. |
| first_indexed | 2024-09-23T16:37:21Z |
| format | Article |
| id | mit-1721.1/93788 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T16:37:21Z |
| publishDate | 2015 |
| publisher | National Academy of Sciences (U.S.) |
| record_format | dspace |
| spelling | mit-1721.1/937882022-09-29T20:22:48Z Structures of benzylsuccinate synthase elucidate roles of accessory subunits in glycyl radical enzyme activation and activity Funk, Michael Andrew Judd, Evan T. Marsh, E. Neil G. Elliott, Sean J. Drennan, Catherine L Massachusetts Institute of Technology. Department of Biology Massachusetts Institute of Technology. Department of Chemistry Funk, Michael Andrew Drennan, Catherine L. Anaerobic degradation of the environmental pollutant toluene is initiated by the glycyl radical enzyme benzylsuccinate synthase (BSS), which catalyzes the radical addition of toluene to fumarate, forming benzylsuccinate. We have determined crystal structures of the catalytic α-subunit of BSS with its accessory subunits β and γ, which both bind a [4Fe-4S] cluster and are essential for BSS activity in vivo. We find that BSSα has the common glycyl radical enzyme fold, a 10-stranded β/α-barrel that surrounds the glycyl radical cofactor and active site. Both accessory subunits β and γ display folds related to high potential iron–sulfur proteins but differ substantially from each other in how they interact with the α-subunit. BSSγ binds distally to the active site, burying a hydrophobic region of BSSα, whereas BSSβ binds to a hydrophilic surface of BSSα that is proximal to the active site. To further investigate the function of BSSβ, we determined the structure of a BSSαγ complex. Remarkably, we find that the barrel partially opens, allowing the C-terminal region of BSSα that houses the glycyl radical to shift within the barrel toward an exit pathway. The structural changes that we observe in the BSSαγ complex center around the crucial glycyl radical domain, thus suggesting a role for BSSβ in modulating the conformational dynamics required for enzyme activity. Accompanying proteolysis experiments support these structural observations. National Science Foundation (U.S.). Graduate Research Fellowship Program (Grant 0645960) National Science Foundation (U.S.) (Grant MCB-0543833) Brookhaven National Laboratory Berkeley Center for Structural Biology 2015-02-05T17:22:48Z 2015-02-05T17:22:48Z 2014-06 2014-03 Article http://purl.org/eprint/type/JournalArticle 0027-8424 1091-6490 http://hdl.handle.net/1721.1/93788 Funk, Michael A., Evan T. Judd, E. Neil G. Marsh, Sean J. Elliott, and Catherine L. Drennan. “Structures of Benzylsuccinate Synthase Elucidate Roles of Accessory Subunits in Glycyl Radical Enzyme Activation and Activity.” Proceedings of the National Academy of Sciences 111, no. 28 (June 30, 2014): 10161–10166. https://orcid.org/0000-0001-5486-2755 en_US http://dx.doi.org/10.1073/pnas.1405983111 Proceedings of the National Academy of Sciences of the United States of America 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 National Academy of Sciences (U.S.) National Academy of Sciences (U.S.) |
| spellingShingle | Funk, Michael Andrew Judd, Evan T. Marsh, E. Neil G. Elliott, Sean J. Drennan, Catherine L Structures of benzylsuccinate synthase elucidate roles of accessory subunits in glycyl radical enzyme activation and activity |
| title | Structures of benzylsuccinate synthase elucidate roles of accessory subunits in glycyl radical enzyme activation and activity |
| title_full | Structures of benzylsuccinate synthase elucidate roles of accessory subunits in glycyl radical enzyme activation and activity |
| title_fullStr | Structures of benzylsuccinate synthase elucidate roles of accessory subunits in glycyl radical enzyme activation and activity |
| title_full_unstemmed | Structures of benzylsuccinate synthase elucidate roles of accessory subunits in glycyl radical enzyme activation and activity |
| title_short | Structures of benzylsuccinate synthase elucidate roles of accessory subunits in glycyl radical enzyme activation and activity |
| title_sort | structures of benzylsuccinate synthase elucidate roles of accessory subunits in glycyl radical enzyme activation and activity |
| url | http://hdl.handle.net/1721.1/93788 https://orcid.org/0000-0001-5486-2755 |
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