Details zur Publikation |
| Kategorie | Textpublikation |
| Referenztyp | Zeitschriften |
| DOI | 10.1021/acs.est.3c00364 |
| Titel (primär) | Insight into the mechanism underlying Dehalococcoides mccartyi strain CBDB1-mediated B12-dependent aromatic reductive dehalogenation |
| Autor | Zhang, S.; Wen, W.; Xia, X.; Ouyang, W.; Mai, B.-X.; Adrian, L.
; Schüürmann, G. |
| Quelle | Environmental Science & Technology |
| Erscheinungsjahr | 2023 |
| Department | OEC; UBT |
| Band/Volume | 57 |
| Heft | 29 |
| Seite von | 10773 |
| Seite bis | 10781 |
| Sprache | englisch |
| Topic | T7 Bioeconomy |
| Supplements | Supplement 1 |
| Keywords | Dehalococcoides; reductive dehalogenation; aromatic halide; thermodynamics; reaction mechanism |
| Abstract | Anaerobic bacteria transform aromatic halides through reductive dehalogenation. This dehalorespiration is catalyzed by the supernucleophilic coenzyme vitamin B12, cob(I)alamin, in reductive dehalogenases. So far, the underlying inner-sphere electron transfer (ET) mechanism has been discussed controversially. In the present study, all 36 chloro-, bromo-, and fluorobenzenes and full-size cobalamin are analyzed at the quantum chemical density functional theory level with respect to a wide range of theoretically possible inner-sphere ET mechanisms. The calculated reaction free energies within the framework of CoI···X (X = F, Cl, and Br) attack rule out most of the inner-sphere pathways. The only route with feasible energetics is a proton-coupled two-ET mechanism that involves a B12 side-chain tyrosine (modeled by phenol) as a proton donor. For 12 chlorobenzenes and 9 bromobenzenes with experimental data from Dehalococcoides mccartyi strain CBDB1, the newly proposed PC-TET mechanism successfully discriminates 16 of 17 active from 4 inactive substrates and correctly predicts the observed regiospecificity to 100%. Moreover, fluorobenzenes are predicted to be recalcitrant in agreement with experimental findings. Conceptually, based on the Bell–Evans–Polanyi principle, the computational approach provides novel mechanistic insights and may serve as a tool for predicting the energetic feasibility of reductive aromatic dehalogenation. |
| dauerhafte UFZ-Verlinkung | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=27397 |
| Zhang, S., Wen, W., Xia, X., Ouyang, W., Mai, B.-X., Adrian, L., Schüürmann, G. (2023): Insight into the mechanism underlying Dehalococcoides mccartyi strain CBDB1-mediated B12-dependent aromatic reductive dehalogenation Environ. Sci. Technol. 57 (29), 10773 - 10781 10.1021/acs.est.3c00364 |
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