Naslov
Biocatalytic approach to chiral fluoroaromatic scaffolds

Autori
Dokli, Irena ; Brkljača, Zlatko ; Švaco, Petra ; Tang, Lixia ; Stepanić, Višnja ; Majerić Elenkov, Maja

Izvornik
Organic & biomolecular chemistry (1477-0520) 20 (2022); 9734-9741

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
biocatalysis ; HHDH ; epoxides ; fluoroaromatic ; kinetic resolution ; computational analysis

Sažetak
Ten different fluorinated aromatic epoxides have been tested as potential substrates for halohydrin dehalogenase (HHDH) HheC. Majority of investigated epoxides are useful building blocks in synthetic chemistry applications, with a number of them being polysubstituted. Moderate to high enantioselectivities (E = 15 - >200) were observed in azidolysis, allowing the synthesis of enantioenriched (R)-azido alcohols containing fluorine in the molecule. In the case where a reaction runs over 50% conversion, enantiopure (S)-epoxides are also available. While o-F-styrene oxide was easily converted to a product, sterically challenging o-CF3-derivative was not accepted by HheC. In silico probing of the binding site indicates that, in order to accommodate o-CF3-derivative in HheC active site, it is necessary to eliminate steric hindrance. Hence, we extended our research by probing several available HheC variants containing relevant modifications in the active site. The active mutant P84V/F86P/T134A/N176A (named HheC-M4) was identified, showing not only high activity towards o-CF3-styrene oxide, but also inverted enantioselectivity (E = 27). Since (S)-enantioselective HHDHs are rare, and therefore valuable for the synthetic application, this enzyme was screened on the initial panel of substrates. The observed (S)-enantioselectivity (E = 1 - 111) is ascribed to formation of the additional space by introduced mutations in HheC-M4, which is also confirmed by classical MD simulations. The successive molecular docking demonstrated that this newly formed tunnel located close to the protein surface is a critical feature of HheC-M4, representing a novel binding site.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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