Expression, Characterisation and Homology Modelling of a Novel Hormone-Sensitive Lipase (HSL)-Like Esterase from Glaciozyma antarctica

• Published in: Catalysts
• Main Authors: Hiryahafira Mohamad Tahir, Raja Noor Zaliha Raja Abd Rahman, Adam Thean Chor Leow, Mohd Shukuri Mohamad Ali
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2020
• Subjects: psychrophilic yeast; hormone-sensitive lipase; glaciozyma antarctica; antarctica and homology modelling; Chemical technology; TP1-1185; Chemistry; QD1-999; Antarc*; Antarctica
• Online Access: https://doi.org/10.3390/catal10010058; https://doaj.org/article/9803915f2ab14075b86273aee0047711

Microorganisms, especially those that survive in extremely cold places such as Antarctica, have gained research attention since they produce a unique feature of the protein, such as being able to withstand at extreme temperature, salinity, and pressure, that make them desired for biotechnological application. Here, we report the first hormone-sensitive lipase (HSL)-like esterase from a Glaciozyma species, a psychrophilic yeast designated as GlaEst12-like esterase. In this study, the putative lipolytic enzyme was cloned, expressed in E. coli , purified, and characterised for its biochemical properties. Protein sequences analysis showed that GlaEst12 shared about 30% sequence identity with chain A of the bacterial hormone-sensitive lipase of E40. It belongs to the H group since it has the conserved motifs of Histidine-Glycine-Glycine-Glycine (HGGG)and Glycine-Aspartate-Serine-Alanine-Glycine (GDSAG) at the amino acid sequences. The recombinant GlaEst12 was successfully purified via one-step Ni-Sepharose affinity chromatography. Interestingly, GlaEst12 showed unusual properties with other enzymes from psychrophilic origin since it showed an optimal temperature ranged between 50−60 °C and was stable at alkaline pH conditions. Unlike other HSL-like esterase, this esterase showed higher activity towards medium-chain ester substrates rather than shorter chain ester. The 3D structure of GlaEst12, predicted by homology modelling using Robetta software, showed a secondary structure composed of mainly α/β hydrolase fold, with the catalytic residues being found at Ser 232 , Glu 341 , and His 371 .