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Discovery, Molecular Mechanisms, and Industrial Applications of Cold-Active Enzymes

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ABSTRACT

Cold-active enzymes constitute an attractive resource for biotechnological applications. Their high catalytic activity at temperatures below 25°C makes them excellent biocatalysts that eliminate the need of heating processes hampering the quality, sustainability, and cost-effectiveness of industrial production. Here we provide a review of the isolation and characterization of novel cold-active enzymes from microorganisms inhabiting different environments, including a revision of the latest techniques that have been used for accomplishing these paramount tasks. We address the progress made in the overexpression and purification of cold-adapted enzymes, the evolutionary and molecular basis of their high activity at low temperatures and the experimental and computational techniques used for their identification, along with protein engineering endeavors based on these observations to improve some of the properties of cold-adapted enzymes to better suit specific applications. We finally focus on examples of the evaluation of their potential use as biocatalysts under conditions that reproduce the challenges imposed by the use of solvents and additives in industrial processes and of the successful use of cold-adapted enzymes in biotechnological and industrial applications.

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Free energy changes between psychrophilic and mesophilic enzymes along the enzyme reaction coordinate from substrates (S) to products (P), according to the transition state theory. The energy of the enzyme-substrate complex for the psychrophilic enzyme (ESP) is higher than for the mesophilic homolog (ESM), due to changes on the free energy of activation caused by decreasing the number of interactions broken to reach the transition state (enthalpic contribution) and increasing the protein flexibility (entropic compensation). These free energy changes lead to an increase in kcat and a concomitant increase in Km. ‡, transition state.
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Figure 6: Free energy changes between psychrophilic and mesophilic enzymes along the enzyme reaction coordinate from substrates (S) to products (P), according to the transition state theory. The energy of the enzyme-substrate complex for the psychrophilic enzyme (ESP) is higher than for the mesophilic homolog (ESM), due to changes on the free energy of activation caused by decreasing the number of interactions broken to reach the transition state (enthalpic contribution) and increasing the protein flexibility (entropic compensation). These free energy changes lead to an increase in kcat and a concomitant increase in Km. ‡, transition state.

Mentions: The contribution of ΔH‡ can be understood in terms of the interactions that are broken while transitioning from the ground enzyme-substrate complex to the transition state of the reaction (Figure 6). Thus, a decrease of the enthalpic contribution translates into a reduction of the number of interactions that must be broken during this process (Siddiqui and Cavicchioli, 2006). This enthalpy decrease for psychrophilic enzymes is consistent with the decrease of the activation energy of the reactions catalyzed by these enzymes, as ΔH‡ = Ea − RT (Lonhienne et al., 2000).


Discovery, Molecular Mechanisms, and Industrial Applications of Cold-Active Enzymes
Free energy changes between psychrophilic and mesophilic enzymes along the enzyme reaction coordinate from substrates (S) to products (P), according to the transition state theory. The energy of the enzyme-substrate complex for the psychrophilic enzyme (ESP) is higher than for the mesophilic homolog (ESM), due to changes on the free energy of activation caused by decreasing the number of interactions broken to reach the transition state (enthalpic contribution) and increasing the protein flexibility (entropic compensation). These free energy changes lead to an increase in kcat and a concomitant increase in Km. ‡, transition state.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5016527&req=5

Figure 6: Free energy changes between psychrophilic and mesophilic enzymes along the enzyme reaction coordinate from substrates (S) to products (P), according to the transition state theory. The energy of the enzyme-substrate complex for the psychrophilic enzyme (ESP) is higher than for the mesophilic homolog (ESM), due to changes on the free energy of activation caused by decreasing the number of interactions broken to reach the transition state (enthalpic contribution) and increasing the protein flexibility (entropic compensation). These free energy changes lead to an increase in kcat and a concomitant increase in Km. ‡, transition state.
Mentions: The contribution of ΔH‡ can be understood in terms of the interactions that are broken while transitioning from the ground enzyme-substrate complex to the transition state of the reaction (Figure 6). Thus, a decrease of the enthalpic contribution translates into a reduction of the number of interactions that must be broken during this process (Siddiqui and Cavicchioli, 2006). This enthalpy decrease for psychrophilic enzymes is consistent with the decrease of the activation energy of the reactions catalyzed by these enzymes, as ΔH‡ = Ea − RT (Lonhienne et al., 2000).

View Article: PubMed Central - PubMed

ABSTRACT

Cold-active enzymes constitute an attractive resource for biotechnological applications. Their high catalytic activity at temperatures below 25°C makes them excellent biocatalysts that eliminate the need of heating processes hampering the quality, sustainability, and cost-effectiveness of industrial production. Here we provide a review of the isolation and characterization of novel cold-active enzymes from microorganisms inhabiting different environments, including a revision of the latest techniques that have been used for accomplishing these paramount tasks. We address the progress made in the overexpression and purification of cold-adapted enzymes, the evolutionary and molecular basis of their high activity at low temperatures and the experimental and computational techniques used for their identification, along with protein engineering endeavors based on these observations to improve some of the properties of cold-adapted enzymes to better suit specific applications. We finally focus on examples of the evaluation of their potential use as biocatalysts under conditions that reproduce the challenges imposed by the use of solvents and additives in industrial processes and of the successful use of cold-adapted enzymes in biotechnological and industrial applications.

No MeSH data available.