Enzyme is stabilized by a protection layer of ionic liquids in supercritical CO2: Insights from molecular dynamic simulation

Monhemi, Hassan; Housaindokht, Mohammad Reza; Bozorgmehr, Mohammad Reza; Googheri, Mohammad Sadegh Sadeghi

doi:10.1016/j.supflu.2012.04.020

Cited by 36 publications

(17 citation statements)

References 50 publications

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“…The loss in the activity in supercritical CO 2 can be attributed to the high structural deviations of the enzyme in comparison with mild aqueous solution as previously reported in our MD simulations [12,14]. We also recently investigated the conformational stability of CALB in compressed propane and found that the enzyme is stable in this solvent [25].…”

Section: Discussionsupporting

confidence: 76%

“…Among scfs, scCO 2 is a popular fluid which has been frequently used as solvent in biocatalyst reactions. Experimental [4][5][6][7][8][9][10][11] and theoretical [12][13][14] investigations showed that the significant conformational changes of the enzymes and proteins occurred with treatment in scCO 2 . Therefore, the utility of this scf is limited due to its undesirable effects on the enzyme stability.…”

Section: Introductionmentioning

confidence: 98%

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The open lid conformation of the lipase is explored in the compressed gas: New insights from molecular dynamic simulation

Housaindokht

Monhemi

2013

Journal of Molecular Catalysis B: Enzymatic

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Section: Discussionsupporting

confidence: 76%

Section: Introductionmentioning

confidence: 98%

The open lid conformation of the lipase is explored in the compressed gas: New insights from molecular dynamic simulation

Housaindokht

Monhemi

2013

Journal of Molecular Catalysis B: Enzymatic

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“…Monhemi et al [100] confirmed it through all-atom MD simulation. It was showed that enzyme and IL molecules formed a supramolecular-like structure in SC-CO 2 , where IL molecules function as a coating layer and protect enzyme from denaturing condition in SC-CO 2 .…”

Section: Biocatalysis In Combined Mixture Solvents Of Ionic Liquid Anmentioning

confidence: 84%

“…Reports have easily been available on the biocatalysis reactions in the mixture solvents of IL and SC-CO 2 fluid [97][98][99][100]. Bogel-Łukasik et al [101] applied a ternary system of [Omim] [PF 6 ]/SC-CO 2 /products for the acylation of (R,S)-2-octanol with succinic anhydride catalyzed by lipase.…”

Section: Biocatalysis In Combined Mixture Solvents Of Ionic Liquid Anmentioning

confidence: 99%

Enzyme Stability and Activity in Non-Aqueous Reaction Systems: A Mini Review

et al. 2016

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Abstract:Enormous interest in biocatalysis in non-aqueous phase has recently been triggered due to the merits of good enantioselectivity, reverse thermodynamic equilibrium, and no water-dependent side reactions. It has been demonstrated that enzyme has high activity and stability in non-aqueous media, and the variation of enzyme activity is attributed to its conformational modifications. This review comprehensively addresses the stability and activity of the intact enzymes in various non-aqueous systems, such as organic solvents, ionic liquids, sub-/super-critical fluids and their combined mixtures. It has been revealed that critical factors such as Log P, functional groups and the molecular structures of the solvents define the microenvironment surrounding the enzyme molecule and affect enzyme tertiary and secondary structure, influencing enzyme catalytic properties. Therefore, it is of high importance for biocatalysis in non-aqueous media to elucidate the links between the microenvironment surrounding enzyme surface and its stability and activity. In fact, a better understanding of the correlation between different non-aqueous environments and enzyme structure, stability and activity can contribute to identifying the most suitable reaction medium for a given biotransformation.

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“…[37] We also showed that how adding ionic liquids (ILs) can stabilize protein conformation in scCO 2 . [38] It was found that CO 2 molecules interact directly with the surface residues which leads to protein instability. These residues are the initial points of enzyme denaturation.…”

Section: Introductionmentioning

confidence: 99%

Chemical modification of biocatalyst for function in supercritical CO2: In silico redesign of stable lipase

Monhemi

Housaindokht

2016

The Journal of Supercritical Fluids

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Graphical Abstract HighlightsPTMs are introduced as a protein stabilization strategy in supercritical condition Lysine acetylation prevents enzyme denaturation at high temperatures in water Acetylation is not so useful for stabilization of enzyme in supercritical CO 2 Methylation and carboxylation efficiently stabilize enzyme in supercritical CO 2 Modification of arginine residues is not so satisfactory in enzyme stabilization Abstract:In spite of excellent properties of supercritical CO 2 in enzyme catalyzed reactions, destabilizing effects of CO 2 molecules on the enzyme structure limits the industrial applications of this green solvent in the field of biocatalysis. Here, based on the substantial role of charged surface residues such as lysines in enzyme inactivation, we introduced for the first time, Post Translational Modifications (PTMs), a famous concept in molecular biology, as a protein stabilization strategy in supercritical condition. Lysine groups were modified using PTM templates to find out more about the exact mechanism of enzyme inactivation in supercritical CO 2 and to explore a new way for protein stabilization in this solvent. We used MD simulation as common tool for in situ examining enzyme structure in supercritical fluids, for the investigation of structural consequence of modifications. Different modifications including acetylation, methylation, phosphorylation, and carboxylation have been applied on the model enzyme. For comparison to CALB structure in supercritical CO 2 , the acetylated enzyme was also simulated in aqueous solvent at 300 and 353 K. Interestingly, acetylation of lysine residues prevents enzyme from denaturation at high temperatures in water, which is in agreement with experimental observation in aqueous solution. However, acetylation is not so useful for stabilization of enzyme in supercritical CO 2 . In contrast, methylation and carboxylation efficiently stabilize enzyme in supercritical CO 2 . Phosphate groups in phosphorylated lysines destabilize enzyme by formation of excess hydrogen bonds by inappropriate groups and perturb enzyme conformation. Moreover, it was found that modification of surface arginine residues was not so satisfactory in stabilization of the enzyme. This finding supports the mechanism of lipase inactivation through direct interaction of CO 2 molecules on lysine residues and formation of carbamates. We think this new exploration not only can open new window for developing enzyme catalyzed reaction in supercritical fluids, but it can shed some light on the mechanism of enzyme inactivation in scCO 2 .

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Enzyme is stabilized by a protection layer of ionic liquids in supercritical CO2: Insights from molecular dynamic simulation

Cited by 36 publications

References 50 publications

The open lid conformation of the lipase is explored in the compressed gas: New insights from molecular dynamic simulation

The open lid conformation of the lipase is explored in the compressed gas: New insights from molecular dynamic simulation

Enzyme Stability and Activity in Non-Aqueous Reaction Systems: A Mini Review

Chemical modification of biocatalyst for function in supercritical CO2: In silico redesign of stable lipase

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