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Environ Int. 2019 Oct;131:104999. doi: 10.1016/j.envint.2019.104999. Epub 2019 Jul 15.

Harnessing fluoroacetate dehalogenase for defluorination of fluorocarboxylic acids: in silico and in vitro approach.

Author information

1
Environment Research Institute, Shandong University, Qingdao 266237, PR China. Electronic address: lyw@sdu.edu.cn.
2
Environment Research Institute, Shandong University, Qingdao 266237, PR China.
3
Key Laboratory of Phytochemistry R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China; Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
4
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
5
School of Environment, Tsinghua University, Beijing 100084, PR China.
6
Key Laboratory of Phytochemistry R&D of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China; Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China. Electronic address: jwang@hunnu.edu.cn.
7
Environment Research Institute, Shandong University, Qingdao 266237, PR China. Electronic address: zqz@sdu.edu.cn.

Abstract

Widely distributed fluorocarboxylic acids have aroused worldwide environmental concerns due to its toxicity, persistence, and bioaccumulation. Enzyme-based eco-friendly biodegradation techniques have become increasingly important in treating fluorocarboxylic acids. Here we utilized in silico and in vitro approaches to investigate the defluorination mechanism of fluoroacetate dehalogenase (FAcD) toward monofluoropropionic acids at atomic-level. The experimentally determined kcat and kM for defluorination of 2-fluoropropionic acid are 330 ± 60 min-1 and 6.12 ± 0.13 mM. The in silico results demonstrated positive/negative correlations between activation barriers and structural parameters (e.g. distance and angle) under different enzymatic conformations. We also screened computationally and tested in vitro (enzyme assay and kinetic study) the catalytic proficiency of FAcD toward polyfluoropropionic acids and perfluoropropionic acids which are known to be challenging for enzymatic degradation. The results revealed potential degradation activity of FAcD enzyme toward 2,3,3,3-tetrafluoropropionic acids. Our work will initiate the development of a new "integrated approach" for enzyme engineering to degrade environmentally persistent fluorocarboxylic acids.

KEYWORDS:

Enzymatic Defluorination; Enzymatic conformations; Quantum mechanics/molecular mechanics; Substitution effect

PMID:
31319293
DOI:
10.1016/j.envint.2019.104999
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