Lipase adsorption on different nanomaterials: a multi-scale simulation study

Abstract

Candida antarctica lipase B (CalB) is an efficient biocatalyst for hydrolysis and esterification, which plays an important role in the production of biodiesel in the bioenergy industries. The ordered immobilisation of lipases on different supports would be significant for its enzymatic catalysis in some biodiesel production processes; however, the underlying mechanisms and the preferred lipase orientation are not well understood yet. In this work, a fundamental understanding of the orientation and adsorption mechanism of lipase on four different nanomaterial surfaces with different surface chemistry are explored in detail by a combination of parallel tempering Monte Carlo (PTMC) and molecular dynamics (MD) simulations. Simulation results show that lipase is strongly adsorbed onto the hydrophobic graphite surface, as reflected by the large contact area and interaction energy; while the adsorption onto the hydrophilic TiO2 surface is weak due to two strongly adhered water layers; meanwhile lipase undergoes desorption and reorientation processes. For CalB adsorption on positively and negatively charged surfaces (NH2-SAM and COOH-SAM), the orientation distributions of lipase are narrow, and opposite orientations are obtained. CalB adsorbed on NH2-SAM has its catalytic centre oriented towards the surface, which is not conducive to the substrate binding; while the catalytic centre faces toward the solution when it is adsorbed on the COOH-SAM. Besides, the native structures of CalB adsorbed on different surfaces are preserved, which indicates lipase as a robust enzyme. The simulation results will promote our understanding on how surface properties of nanomaterials, such as charge or hydrophobicity, will affect lipase immobilisation, and help us in the rational design and development of immobilised lipase carriers.

Immobilization on octyl‐agarose beads and some catalytic features of commercial preparations of lipase a from Candida antarctica (Novocor ADL): Comparison with immobilized lipase B from Candida antarctica

“…CALB is a lipase having a very small lid that does not isolate the activity center from the medium . That way, the hydrophobic pocket surrounding the active center is smaller than in the case of CALA, and the enzyme may be immobilized on hydrophobic surfaces, but not in the open form of other lipases. Neither may it be used as chromatographic matrix to purify nor immobilize lipases.…”

Molecular Simulations of Cytochrome c Adsorption on a Bare Gold Surface: Insights for the Hindrance of Electron Transfer

“…It has been successfully used in some of our previous works [34][35][36][37][38][39] to quickly obtain the preferential adsorption orientations. With these preliminarily optimized orientations from PTMC as the initial orientations, MD simulations were performed by using the GolP-CHARMM force field 32 to explore the adsorption behavior of Cyt-c on Au (111) surface.…”

From Protein Features to Sensing Surfaces

“…Enzymes such as lipase ( Figure 1 b) and cholesterol oxidase, which are active on hydrophobic substrates, often present an enrichment of hydrophobic residues in the proximity of the active site. Lipase B from Candida antarctica is strongly adsorbed to hydrophobic surfaces such as graphite [ 12 ] and porous styrene–divinylbenzene beads [ 13 ]. Immobilization of lipase from Pseudomonas cepacia into siliceous mesocellular foams with different degrees of hydrophobicity demonstrated how increased hydrophobicity led to an enhancement of catalytic activity [ 14 ].…”