Effects of phosphonium‐based ionic liquids on the lipase activity evaluated by experimental results and molecular docking

Abstract

In this work, the effect of several phosphonium‐based ionic liquids (ILs) on the activity of lipase from Burkholderia cepacia (BCL) was evaluated by experimental assays and molecular docking. ILs comprising different cations ([P4444]+, [P444(14)]+, [P666(14)]+) and anions (Cl−, Br−, [Deca]−, [Phosp]−, [NTf2]−) were investigated to appraise the individual roles of IL ions on the BCL activity. From the activity assays, it was found that an increase in the cation alkyl chain length leads to a decrease on the BCL enzymatic activity. ILs with the anions [Phosp]− and [NTf2]− increase the BCL activity, while the remaining [P666(14)]‐based ILs with the Cl−, Br−, and [Deca]− anions display a negative effect on the BCL activity. The highest activity of BCL was identified with the IL [P666(14)][NTf2] (increase in the enzymatic activity of BCL by 61% at 0.055 mol·L−1). According to the interactions determined by molecular docking, IL cations preferentially interact with the Leu17 residue (amino acid present in the BCL oxyanion hole). The anion [Deca]− has a higher binding affinity compared to Cl− and Br−, and mainly interacts by hydrogen‐bonding with Ser87, an amino acid residue which constitutes the catalytic triad of BCL. The anions [Phosp]− and [NTf2]− have high binding energies (−6.2 and −5.6 kcal·mol−1, respectively) with BCL, and preferentially interact with the side chain amino acids of the enzyme and not with residues of the active site. Furthermore, FTIR analysis of the protein secondary structure show that ILs that lead to a decrease on the α‐helix content result in a higher BCL activity, which may be derived from an easier access of the substrate to the BCL active site.

Lipase activation by molecular bioimprinting: The role of interactions between fatty acids and enzyme active site

“…6 The use of lipases as a biocatalyst has advantages of high selectivity and specificity, in addition to being able to maintain catalytic activity in aqueous and nonaqueous solutions. 7,8 Thus, lipases have been very attractive for numerous industrial applications, 9 such as pharmaceuticals, 10 fatty acids, 11 biofuels, 12 and food. 13 For this reasons, the use of these biocatalysts is a very promising alternative for developing environmentally friendly processes.…”

Applications of Ionic Liquids in Whole-Cell and Isolated Enzyme Biocatalysis

“…The ability of lipase from Burkholderia cepacia to catalyse olive oil hydrolysis was measured in aqueous buffer mixed with phosphonium ILs (0.011–0.055 mol/L) with different anions [ 79 ]. Enhanced relative activities of 144 and 162 were observed in [P 6,6,6,14 ][Phosp] and [P 6,6,6,14 ][NTf 2 ] at 0.055 mol/L concentration.…”

Facilitating enzymatic reactions by using ionic liquids: A mini review

“…Enzymes are extensively used in industrial and research biocatalysis (in the pharmaceutical, waste management, food, and energy sectors). Furthermore, enzymes offer advantageous ecofriendly features compared with chemical catalysis [12]. Many studies have focused on the dynamic and structural characteristics of enzymes and other proteins dissolved in IL media [12,16,17].…”

“…Furthermore, enzymes offer advantageous ecofriendly features compared with chemical catalysis [12]. Many studies have focused on the dynamic and structural characteristics of enzymes and other proteins dissolved in IL media [12,16,17]. Reactions catalyzed by enzymes can be performed in an IL-based monophasic or biphasic system consisting of ILs/supercritical CO 2 , ILs/molecular solvents, or ILs/ water.…”