Diiron Oxidation State Control of Substrate Access to the Active Site of Soluble Methane Monooxygenase Mediated by the Regulatory Component
The regulatory component (MMOB) of soluble methane monooxygenase (sMMO) has a unique N-terminal tail not found in regulatory proteins of other bacterial multicomponent monooxygenases. This N-terminal tail is indispensable for proper function, yet its solution structure and role in catalysis remain e...
| Main Authors: | , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
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American Chemical Society (ACS)
2015
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| Online Access: | http://hdl.handle.net/1721.1/95475 https://orcid.org/0000-0002-2693-4982 |
| _version_ | 1811095872904101888 |
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| author | Wang, Weixue Lippard, Stephen J. |
| author2 | Massachusetts Institute of Technology. Department of Chemistry |
| author_facet | Massachusetts Institute of Technology. Department of Chemistry Wang, Weixue Lippard, Stephen J. |
| author_sort | Wang, Weixue |
| collection | MIT |
| description | The regulatory component (MMOB) of soluble methane monooxygenase (sMMO) has a unique N-terminal tail not found in regulatory proteins of other bacterial multicomponent monooxygenases. This N-terminal tail is indispensable for proper function, yet its solution structure and role in catalysis remain elusive. Here, by using double electron–electron resonance (DEER) spectroscopy, we show that the oxidation state of the hydroxylase component, MMOH, modulates the conformation of the N-terminal tail in the MMOH–2MMOB complex, which in turn facilitates catalysis. The results reveal that the N-terminal tail switches from a relaxed, flexible conformational state to an ordered state upon MMOH reduction from the diiron(III) to the diiron(II) state. This observation suggests that some of the crystallographically observed allosteric effects that result in the connection of substrate ingress cavities in the MMOH–2MMOB complex may not occur in solution in the diiron(III) state. Thus, O[subscript 2] may not have easy access to the active site until after reduction of the diiron center. The observed conformational change is also consistent with a higher binding affinity of MMOB to MMOH in the diiron(II) state, which may allow MMOB to displace more readily the reductase component (MMOR) from MMOH following reduction. |
| first_indexed | 2024-09-23T16:31:58Z |
| format | Article |
| id | mit-1721.1/95475 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T16:31:58Z |
| publishDate | 2015 |
| publisher | American Chemical Society (ACS) |
| record_format | dspace |
| spelling | mit-1721.1/954752022-09-29T20:03:28Z Diiron Oxidation State Control of Substrate Access to the Active Site of Soluble Methane Monooxygenase Mediated by the Regulatory Component Wang, Weixue Lippard, Stephen J. Massachusetts Institute of Technology. Department of Chemistry Lippard, Stephen J. Wang, Weixue The regulatory component (MMOB) of soluble methane monooxygenase (sMMO) has a unique N-terminal tail not found in regulatory proteins of other bacterial multicomponent monooxygenases. This N-terminal tail is indispensable for proper function, yet its solution structure and role in catalysis remain elusive. Here, by using double electron–electron resonance (DEER) spectroscopy, we show that the oxidation state of the hydroxylase component, MMOH, modulates the conformation of the N-terminal tail in the MMOH–2MMOB complex, which in turn facilitates catalysis. The results reveal that the N-terminal tail switches from a relaxed, flexible conformational state to an ordered state upon MMOH reduction from the diiron(III) to the diiron(II) state. This observation suggests that some of the crystallographically observed allosteric effects that result in the connection of substrate ingress cavities in the MMOH–2MMOB complex may not occur in solution in the diiron(III) state. Thus, O[subscript 2] may not have easy access to the active site until after reduction of the diiron center. The observed conformational change is also consistent with a higher binding affinity of MMOB to MMOH in the diiron(II) state, which may allow MMOB to displace more readily the reductase component (MMOR) from MMOH following reduction. National Institute of General Medical Sciences (U.S.) (Grant GM032134) 2015-02-24T15:34:50Z 2015-02-24T15:34:50Z 2014-01 2013-12 Article http://purl.org/eprint/type/JournalArticle 0002-7863 1520-5126 http://hdl.handle.net/1721.1/95475 Wang, Weixue, and Stephen J. Lippard. “Diiron Oxidation State Control of Substrate Access to the Active Site of Soluble Methane Monooxygenase Mediated by the Regulatory Component.” Journal of the American Chemical Society 136, no. 6 (February 12, 2014): 2244–2247. © 2014 American Chemical Society https://orcid.org/0000-0002-2693-4982 en_US http://dx.doi.org/10.1021/ja412351b Journal of the American Chemical Society 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 American Chemical Society (ACS) PMC |
| spellingShingle | Wang, Weixue Lippard, Stephen J. Diiron Oxidation State Control of Substrate Access to the Active Site of Soluble Methane Monooxygenase Mediated by the Regulatory Component |
| title | Diiron Oxidation State Control of Substrate Access to the Active Site of Soluble Methane Monooxygenase Mediated by the Regulatory Component |
| title_full | Diiron Oxidation State Control of Substrate Access to the Active Site of Soluble Methane Monooxygenase Mediated by the Regulatory Component |
| title_fullStr | Diiron Oxidation State Control of Substrate Access to the Active Site of Soluble Methane Monooxygenase Mediated by the Regulatory Component |
| title_full_unstemmed | Diiron Oxidation State Control of Substrate Access to the Active Site of Soluble Methane Monooxygenase Mediated by the Regulatory Component |
| title_short | Diiron Oxidation State Control of Substrate Access to the Active Site of Soluble Methane Monooxygenase Mediated by the Regulatory Component |
| title_sort | diiron oxidation state control of substrate access to the active site of soluble methane monooxygenase mediated by the regulatory component |
| url | http://hdl.handle.net/1721.1/95475 https://orcid.org/0000-0002-2693-4982 |
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