Identification and Biochemical Characterization of a Novel Hormone-Sensitive Lipase Family Esterase Est19 from the Antarctic Bacterium Pseudomonas sp. E2-15

• Published in: Biomolecules
• Main Authors: Xiaoyu Liu, Mingyang Zhou, Shu Xing, Tao Wu, Hailun He, John Kevin Bielicki, Jianbin Chen
• Format: Text
• Language: English
• Published: Multidisciplinary Digital Publishing Institute 2021
• Subjects: esterase; Antarctic; HSL family; GESAG motif; The Antarctic; Antarc*
• Online Access: https://doi.org/10.3390/biom11111552

Esterases represent an important class of enzymes with a wide variety of industrial applications. A novel hormone-sensitive lipase (HSL) family esterase, Est19, from the Antarctic bacterium Pseudomonas sp. E2-15 is identified, cloned, and expressed. The enzyme possesses a GESAG motif containing an active serine (S) located within a highly conserved catalytic triad of Ser155, Asp253, and His282 residues. The catalytic efficiency (kcat/Km) of Est19 for the pNPC6 substrate is 148.68 s−1mM−1 at 40 °C. Replacing Glu154 juxtaposed to the critical catalytic serine with Asp (E154→D substitution) reduced the activity and catalytic efficiency of the enzyme two-fold, with little change in the substrate affinity. The wild-type enzyme retained near complete activity over a temperature range of 10–60 °C, while ~50% of its activity was retained at 0 °C. A phylogenetic analysis suggested that Est19 and its homologs may represent a new subfamily of HSL. The thermal stability and stereo-specificity suggest that the Est19 esterase may be useful for cold and chiral catalyses.