Insights into the mechanism and regulation of the CbbQO-type Rubisco activase, a MoxR AAA+ ATPase
The vast majority of biological carbon dioxide fixation relies on the function of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). In most cases the enzyme exhibits a tendency to become inhibited by its substrate RuBP and other sugar phosphates. The inhibition is counteracted by diverse mo...
| Main Authors: | , , , , , , |
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| Format: | Journal Article |
| Language: | English |
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2021
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| Online Access: | https://hdl.handle.net/10356/153986 |
| _version_ | 1826130261065072640 |
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| author | Tsai, Candace Yi-Chin Ye, Fuzhou Liew, Lynette Liu, Di Bhushan, Shashi Gao, Yong-Gui Mueller-Cajar, Oliver |
| author2 | School of Biological Sciences |
| author_facet | School of Biological Sciences Tsai, Candace Yi-Chin Ye, Fuzhou Liew, Lynette Liu, Di Bhushan, Shashi Gao, Yong-Gui Mueller-Cajar, Oliver |
| author_sort | Tsai, Candace Yi-Chin |
| collection | NTU |
| description | The vast majority of biological carbon dioxide fixation relies on the function of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). In most cases the enzyme exhibits a tendency to become inhibited by its substrate RuBP and other sugar phosphates. The inhibition is counteracted by diverse molecular chaperones known as Rubisco activases (Rcas). In some chemoautotrophic bacteria, the CbbQO-type Rca Q2O2 repairs inhibited active sites of hexameric form II Rubisco. The 2.2-Å crystal structure of the MoxR AAA+ protein CbbQ2 from Acidithiobacillus ferrooxidans reveals the helix 2 insert (H2I) that is critical for Rca function and forms the axial pore of the CbbQ hexamer. Negative-stain electron microscopy shows that the essential CbbO adaptor protein binds to the conserved, concave side of the CbbQ2 hexamer. Site-directed mutagenesis supports a model in which adenosine 5'-triphosphate (ATP)-powered movements of the H2I are transmitted to CbbO via the concave residue L85. The basal ATPase activity of Q2O2 Rca is repressed but strongly stimulated by inhibited Rubisco. The characterization of multiple variants where this repression is released indicates that binding of inhibited Rubisco to the C-terminal CbbO VWA domain initiates a signal toward the CbbQ active site that is propagated via elements that include the CbbQ α4-β4 loop, pore loop 1, and the presensor 1-β hairpin (PS1-βH). Detailed mechanistic insights into the enzyme repair chaperones of the highly diverse CO₂ fixation machinery of Proteobacteria will facilitate their successful implementation in synthetic biology ventures. |
| first_indexed | 2024-10-01T07:53:34Z |
| format | Journal Article |
| id | ntu-10356/153986 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T07:53:34Z |
| publishDate | 2021 |
| record_format | dspace |
| spelling | ntu-10356/1539862022-02-21T08:37:32Z Insights into the mechanism and regulation of the CbbQO-type Rubisco activase, a MoxR AAA+ ATPase Tsai, Candace Yi-Chin Ye, Fuzhou Liew, Lynette Liu, Di Bhushan, Shashi Gao, Yong-Gui Mueller-Cajar, Oliver School of Biological Sciences Science::Biological sciences Rubisco Activase Carbon Fixation The vast majority of biological carbon dioxide fixation relies on the function of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). In most cases the enzyme exhibits a tendency to become inhibited by its substrate RuBP and other sugar phosphates. The inhibition is counteracted by diverse molecular chaperones known as Rubisco activases (Rcas). In some chemoautotrophic bacteria, the CbbQO-type Rca Q2O2 repairs inhibited active sites of hexameric form II Rubisco. The 2.2-Å crystal structure of the MoxR AAA+ protein CbbQ2 from Acidithiobacillus ferrooxidans reveals the helix 2 insert (H2I) that is critical for Rca function and forms the axial pore of the CbbQ hexamer. Negative-stain electron microscopy shows that the essential CbbO adaptor protein binds to the conserved, concave side of the CbbQ2 hexamer. Site-directed mutagenesis supports a model in which adenosine 5'-triphosphate (ATP)-powered movements of the H2I are transmitted to CbbO via the concave residue L85. The basal ATPase activity of Q2O2 Rca is repressed but strongly stimulated by inhibited Rubisco. The characterization of multiple variants where this repression is released indicates that binding of inhibited Rubisco to the C-terminal CbbO VWA domain initiates a signal toward the CbbQ active site that is propagated via elements that include the CbbQ α4-β4 loop, pore loop 1, and the presensor 1-β hairpin (PS1-βH). Detailed mechanistic insights into the enzyme repair chaperones of the highly diverse CO₂ fixation machinery of Proteobacteria will facilitate their successful implementation in synthetic biology ventures. Ministry of Education (MOE) Nanyang Technological University This work was funded by a Nanyang Technological University startup grant (to O.M.-C.) and by Ministry of Education (MOE) of Singapore Tier 2 grants to O.M.-C. (MOE2016-T2-2-088), Y.-G.G. (MOE2015-T2-1-078), and S.B. (MOE2017-T2-2-089). 2021-12-14T00:34:59Z 2021-12-14T00:34:59Z 2020 Journal Article Tsai, C. Y., Ye, F., Liew, L., Liu, D., Bhushan, S., Gao, Y. & Mueller-Cajar, O. (2020). Insights into the mechanism and regulation of the CbbQO-type Rubisco activase, a MoxR AAA+ ATPase. Proceedings of the National Academy of Sciences of the United States of America, 117(1), 381-387. https://dx.doi.org/10.1073/pnas.1911123117 0027-8424 https://hdl.handle.net/10356/153986 10.1073/pnas.1911123117 31848241 2-s2.0-85077653567 1 117 381 387 en MOE2016-T2-2-088 MOE2015-T2-1-078 MOE2017-T2-2-089 Proceedings of the National Academy of Sciences of the United States of America 10.21979/N9/K4IROM © 2020 The Author(s) (Published under the PNAS license). All rights reserved. |
| spellingShingle | Science::Biological sciences Rubisco Activase Carbon Fixation Tsai, Candace Yi-Chin Ye, Fuzhou Liew, Lynette Liu, Di Bhushan, Shashi Gao, Yong-Gui Mueller-Cajar, Oliver Insights into the mechanism and regulation of the CbbQO-type Rubisco activase, a MoxR AAA+ ATPase |
| title | Insights into the mechanism and regulation of the CbbQO-type Rubisco activase, a MoxR AAA+ ATPase |
| title_full | Insights into the mechanism and regulation of the CbbQO-type Rubisco activase, a MoxR AAA+ ATPase |
| title_fullStr | Insights into the mechanism and regulation of the CbbQO-type Rubisco activase, a MoxR AAA+ ATPase |
| title_full_unstemmed | Insights into the mechanism and regulation of the CbbQO-type Rubisco activase, a MoxR AAA+ ATPase |
| title_short | Insights into the mechanism and regulation of the CbbQO-type Rubisco activase, a MoxR AAA+ ATPase |
| title_sort | insights into the mechanism and regulation of the cbbqo type rubisco activase a moxr aaa atpase |
| topic | Science::Biological sciences Rubisco Activase Carbon Fixation |
| url | https://hdl.handle.net/10356/153986 |
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