期刊
FRONTIERS IN MICROBIOLOGY
卷 13, 期 -, 页码 -出版社
FRONTIERS MEDIA SA
DOI: 10.3389/fmicb.2022.855658
关键词
esterase; Antarctic; bacterium; soil; new esterase family XXI
类别
资金
- National Natural Science Foundation of China [31400002, 22171154, 31370104]
- Natural Science Foundation of Shandong Province [ZR2020QB114, ZR2020QB008]
- Youth Innovative Talents Recruitment and Cultivation Program of Shandong Higher Education
- Qilu University of Technology (Shandong Academy of Sciences) International Cooperation Fund [QLUTGJHZ2018002]
This study identified a novel esterase gene (Est33) from an Antarctic bacterium and characterized its biochemical properties. The Est33 enzyme was found to be a cold-active esterase with optimal activity towards a specific substrate.
Studies of microorganisms from extreme environments can sometimes reveal novel proteins with unique properties. Here, we identified a novel esterase gene (Est33) from an Antarctic bacterium. The protein was expressed and purified for biochemical characterizations. Site-mutation variants including S94A, D205A, and H233A were constructed to explore the structure-function relationship of the catalytic triad of Est33, and we found mutating Ser(94), Asp(205), and His(233) residues lead to a complete loss of enzyme activity. In addition, the catalytic Ser(94) located in a conserved pentapeptide motif GVSWG. Phylogenetic analysis showed that Est33 and its closely related homologs belonged to an independent group apart from other known family members, indicating that Est33 represented a new family of esterase. The Est33 enzyme was found to be a cold-active esterase retaining 25%-100% activity from 10 degrees C to 30 degrees C and to have optimal catalytic activity toward p-nitrophenol acetate (30 degrees C and pH7.5). The serine modifying reagent phenylmethylsulfonyl fluoride inhibited the activity of Est33 by 77.34%, while thiol reagents such as dithiol threitol (DTT) activated the enzyme by 3-fold. Metal chelating reagents EDTA had no effects, indicating that Est33 is not a metalloenzyme. Collectively, these results indicate that Est33 constitutes the first member of a novel esterase family XXI that has been identified.
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