Spin-orbit coupling effects in O(2) activation by cofactor-independent 2,4-dioxygenase
The O2 (dioxygen) is paramagnetic molecule with two non-paired electron spins and triplet ground state (S = 1) while majority of organic molecules are diamagnetic species; they have all electron spins paired and the singlet ground state with the total spin S = 0. Oxygenases catalyze a concerted inse...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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National Academy of Sciences of Ukraine, Palladin Institute of Biochemistry
2019-02-01
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| Series: | The Ukrainian Biochemical Journal |
| Subjects: | |
| Online Access: | http://ukrbiochemjournal.org/wp-content/uploads/2019/01/Minaev_1_19.pdf |
| _version_ | 1797422299562901504 |
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| author | B. F. Minaev R. R. Valiev |
| author_facet | B. F. Minaev R. R. Valiev |
| author_sort | B. F. Minaev |
| collection | DOAJ |
| description | The O2 (dioxygen) is paramagnetic molecule with two non-paired electron spins and triplet ground state (S = 1) while majority of organic molecules are diamagnetic species; they have all electron spins paired and the singlet ground state with the total spin S = 0. Oxygenases catalyze a concerted insertion of the triplet dioxygen into organic (diamagnetic) molecules in a strictly spin-forbidden process and this puzzle is not solved so far in modern enzymology. Many oxidases and oxygenases utilize the π-conjugated organic cofactor (like flavins, pterins) in a singlet ground state and reaction of cofactor with O2 is still spin-forbidden. It is clear that the protein environment in the enzyme active-site “helps” in some way to overcome spin prohibition, but this environment is definitely diamagnetic and the spin-puzzle still exists. Some oxidases and oxygenases use paramagnetic metal ions as a cofactor; in this case the spin prohibition is formally reduced. In recent years, a numbers of oxidative enzymes are discovered which do not contain any cofactor. In the present work, we considered a rather popular cofactor-free bacterial 2,4-dioxygenase and its oxygenolytic reactions with 2-n-alkyl-3-hydroxy-4(1H)-quinolones (AHQ’s). We presented results of quantum-chemical calculations of intermediate diradical proposed recently for direct reaction of dioxygen with AHQ substrate and made conclusion about the mechanism of spin-catalysis. |
| first_indexed | 2024-03-09T07:30:11Z |
| format | Article |
| id | doaj.art-5e5beb0fe37c4bb28ae3b56ae0ed18e5 |
| institution | Directory Open Access Journal |
| issn | 2409-4943 2413-5003 |
| language | English |
| last_indexed | 2024-03-09T07:30:11Z |
| publishDate | 2019-02-01 |
| publisher | National Academy of Sciences of Ukraine, Palladin Institute of Biochemistry |
| record_format | Article |
| series | The Ukrainian Biochemical Journal |
| spelling | doaj.art-5e5beb0fe37c4bb28ae3b56ae0ed18e52023-12-03T06:27:16ZengNational Academy of Sciences of Ukraine, Palladin Institute of BiochemistryThe Ukrainian Biochemical Journal2409-49432413-50032019-02-01911384610.15407/ubj91.01.038Spin-orbit coupling effects in O(2) activation by cofactor-independent 2,4-dioxygenaseB. F. Minaev0R. R. Valiev1Bohdan Khmelnytsky National University of Cherkasy, UkraineRoyal Institute of Technology, Stockholm, SwedenThe O2 (dioxygen) is paramagnetic molecule with two non-paired electron spins and triplet ground state (S = 1) while majority of organic molecules are diamagnetic species; they have all electron spins paired and the singlet ground state with the total spin S = 0. Oxygenases catalyze a concerted insertion of the triplet dioxygen into organic (diamagnetic) molecules in a strictly spin-forbidden process and this puzzle is not solved so far in modern enzymology. Many oxidases and oxygenases utilize the π-conjugated organic cofactor (like flavins, pterins) in a singlet ground state and reaction of cofactor with O2 is still spin-forbidden. It is clear that the protein environment in the enzyme active-site “helps” in some way to overcome spin prohibition, but this environment is definitely diamagnetic and the spin-puzzle still exists. Some oxidases and oxygenases use paramagnetic metal ions as a cofactor; in this case the spin prohibition is formally reduced. In recent years, a numbers of oxidative enzymes are discovered which do not contain any cofactor. In the present work, we considered a rather popular cofactor-free bacterial 2,4-dioxygenase and its oxygenolytic reactions with 2-n-alkyl-3-hydroxy-4(1H)-quinolones (AHQ’s). We presented results of quantum-chemical calculations of intermediate diradical proposed recently for direct reaction of dioxygen with AHQ substrate and made conclusion about the mechanism of spin-catalysis.http://ukrbiochemjournal.org/wp-content/uploads/2019/01/Minaev_1_19.pdf2-methyl-3-hydroxy-4(1H)-quinolone4-dioxygenasebacterial 1-H-3-hydroxy-4-oxoquinaldine 2cofactor-independent oxygenasesdioxygenradical pairspin-orbit couplingsuperoxide anion |
| spellingShingle | B. F. Minaev R. R. Valiev Spin-orbit coupling effects in O(2) activation by cofactor-independent 2,4-dioxygenase The Ukrainian Biochemical Journal 2-methyl-3-hydroxy-4(1H)-quinolone 4-dioxygenase bacterial 1-H-3-hydroxy-4-oxoquinaldine 2 cofactor-independent oxygenases dioxygen radical pair spin-orbit coupling superoxide anion |
| title | Spin-orbit coupling effects in O(2) activation by cofactor-independent 2,4-dioxygenase |
| title_full | Spin-orbit coupling effects in O(2) activation by cofactor-independent 2,4-dioxygenase |
| title_fullStr | Spin-orbit coupling effects in O(2) activation by cofactor-independent 2,4-dioxygenase |
| title_full_unstemmed | Spin-orbit coupling effects in O(2) activation by cofactor-independent 2,4-dioxygenase |
| title_short | Spin-orbit coupling effects in O(2) activation by cofactor-independent 2,4-dioxygenase |
| title_sort | spin orbit coupling effects in o 2 activation by cofactor independent 2 4 dioxygenase |
| topic | 2-methyl-3-hydroxy-4(1H)-quinolone 4-dioxygenase bacterial 1-H-3-hydroxy-4-oxoquinaldine 2 cofactor-independent oxygenases dioxygen radical pair spin-orbit coupling superoxide anion |
| url | http://ukrbiochemjournal.org/wp-content/uploads/2019/01/Minaev_1_19.pdf |
| work_keys_str_mv | AT bfminaev spinorbitcouplingeffectsino2activationbycofactorindependent24dioxygenase AT rrvaliev spinorbitcouplingeffectsino2activationbycofactorindependent24dioxygenase |