Title
A novel enantioselective SGNH family esterase (NmSGNH1) from Neisseria meningitides: Characterization, mutational analysis, and ester synthesis
Author
Wanki Yoo, Ly Thi Huong Luu Le, Jun Hyuck Lee, Kyeong Kyu Kim, T. Doohun Kim
Year
2019
Journal
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids
Abstract
In Neisseria sp., SGNH family esterases are involved in bacterial pathogenesis as well as cell wall peptidoglycan maturation. Here, a novel enantioselective SGNH family esterase (NmSGNH1) from Neisseria meningitidis, which has sequence similarity to carbohydrate esterase (CE3) family, was catalytically characterized and functionally explored. NmSGNH1 exhibited a wide range of substrate specificities including naproxol acetate, tert-butyl acetate, glucose pentaacetate as well as p-nitrophenyl esters. Deletion of C-terminal residues (NmSGNH1Δ11) led to the altered substrate specificity, reduced catalytic activity, and increased thermostability. Furthermore, a hydrophobic residue of Leu92 in the substrate-binding pocket was identified to be critical in catalytic activity, thermostability, kinetics, and enantioselectivity. Interestingly, immobilization of NmSGNH1 by hybrid nanoflowers (hNFs) and crosslinked enzyme aggregates (CLEAs) showed increased level of activity, recycling property, and enhanced stability. Finally, synthesis of butyl acetate, oleic acid esters, and fatty acid methyl esters (FAMEs) were verified. In summary, this work provides a molecular understanding of substrate specificities, catalytic regulation, immobilization, and industrial applications of a novel SGNH family esterase from Neisseria meningitidis.
Instrument
J-810, FP-8200
Keywords
Circular dichroism, Secondary structure, Protein folding, Thermal stability, Fluorescence, Protein structure, Chemical stability, Protein denaturation, Biochemistry