Laccase Enzymes: Purification, Structure to Catalysis and Tailoring (original) (raw)
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Fungal laccase - a versatile enzyme for biotechnological applications
Laccase belongs to the small group of enzymes called the blue multi copper oxidases. Laccase is widely distributed in higher plants and fungi. In fungi, laccase is present in Ascomycetes, Deuteromycetes, Basidiomycetes and is particularly abundant in many white-rot fungi that degrade lignin. Laccases have been subject of intensive research in the last decades due to their broad substrate specificity. In the recent years, their uses span from the textile to the pulp and paper industries, and food applications to bioremediation processes. Laccases also have uses in organic synthesis, where typical substrates are phenols and amines, and the reaction products are dimers and oligomers derived from the coupling of reactive radical intermediates. More recently, they have found applications in other field such as in the design of biosensors and biofuel cells. In this review, the occurrence, mode of action, general properties, production and immobilization of laccases will be discussed. Here, we will also provide discussion of potential applications of these blue enzymes.
Laccases – enzymes with an unlimited potential
2017
Laccases (EC 1.10.3.2) are among the few enzymes, the history of which dates back to the 19 century. These oxidoreductases are present in almost all known fungi, some species of higher plants and insects. Moreover, in recent years, these enzymes have also been found in some bacterial organisms. Due to their significant properties and structure of the catalytic centre, laccases have been classified as the multicopper oxidases (MCOs). These enzymes are able to catalyse the oxidation of phenolic and non-phenolic compounds, with the aid of small molecules referred to as mediators. Thanks to their diverse nature, laccases have gained attention of both scientists and entrepreneurs from all over the world. Their significance is reflected in countless scientific and industrial applications, wherein laccases have become inseparable from chemical syntheses, the food industry, textile industry, biosensor design and the environmental protection. This paper gathers the most important information...
Expression of industrially relevant laccases: prokaryotic style
Trends in Biotechnology, 2011
Laccases are a class of multi-copper oxidases (MCOs) that catalyze the one-electron oxidation of four equivalents of a reducing substrate, with the concomitant fourelectron reduction of dioxygen to water. They can catalyze a multitude of reactions, including the degradation of polymers and oxidative coupling of phenolic compounds, positioning them as significant industrial enzymes. Although fungal laccases are well known and well characterized, only recently has in silico biology led to rapid advances in the discovery, characterization and engineered expression of prokaryotic laccases. We describe the recent burgeoning of prokaryotic laccases, their catalytic properties, structural features and molecular evolution, vis-a`-vis fungal laccases where possible. Special focus is given to the application of laccases to the emerging cellulosic biofuel industry.
Designer laccases: a vogue for high-potential fungal enzymes?
Trends in Biotechnology, 2010
Laccases are blue multicopper oxidases that catalyse the four-electron reduction of O 2 to water coupled with the oxidation of small organic substrates. Secreted basidiomycete white-rot fungal laccases orchestrate this with high thermodynamic efficiency, making these enzymes excellent candidates for exploitation as industrial oxidants. However, these fungi are less tractable genetically than the ascomycetes, which predominantly produce lower-potential laccases. We address the state-ofplay regarding expression of high reduction potential laccases in heterologous hosts, and issues regarding enzyme glycosylation status. We describe the synergistic role of structural biology, particularly in unmasking structure-function relationships following genetic modification and their collective impact on laccase yields. Such recent research draws closer the prospect of industrial quantities of designer, fit-for-purpose laccases.
Laccases of prokaryotic origin: enzymes at the interface of protein science and protein technology
Cellular and Molecular Life Sciences, 2015
The ubiquitous members of the multicopper oxidase family of enzymes oxidize a range of aromatic substrates such as polyphenols, methoxy-substituted phenols, amines and inorganic compounds, concomitantly with the reduction of molecular dioxygen to water. This family of enzymes can be broadly divided into two functional classes: metalloxidases and laccases. Several prokaryotic metalloxidases have been described in the last decade showing a robust activity towards metals, such as Cu(I), Fe(II) or Mn(II) and have been implicated in the metal metabolism of the corresponding microorganisms. Many laccases, with a superior efficiency for oxidation of organic compounds when compared with metals, have also been identified and characterized from prokaryotes, playing roles that more closely conform to those of intermediary metabolism. This review aims to present an update of current knowledge on prokaryotic multicopper oxidases, with a special emphasis on laccases, anticipating their enormous potential for industrial and environmental applications.
Laccases: structure, reactions, distribution
Micron, 2004
Laccases (EC 1.10.3.2, p-diphenol: dioxygen oxidoreductases) are multi-copper proteins that use molecular oxygen to oxidize various aromatic and non-aromatic compounds by a radical-catalyzed reaction mechanism. The enzymes are involved in the pathogenicity, immunity and morphogenesis of organisms and in the metabolic turnover of complex organic substances such as lignin or humic matter. Owing to their high non-specific oxidation capacity, laccases are useful biocatalysts for diverse biotechnological applications. Until recently, laccases were only found in eukaryotes (fungi, higher plants, insects), but now there is strong evidence for their widespread distribution in prokaryotes and the first crystal structure of a bacterial laccase is already available. Phylogenetically, laccases are members of the multi-copper protein family including ascorbate oxidase, ceruloplasmin and bilirubin oxidase.
Structure-activity investigation on laccases by computational and site directed mutagenesis studies
2016
Laccases belong to multi copper oxidase enzyme family (EC 1.10.3.2). Their capacity to oxidize a wide range of substrates makes them very attractive for the industry and are growing in importance for environmentally-friendly synthesis. Laccases have three different copper sites including, type 1 (T1), type 2 (T2) and type 3 (T3). The function of the T1 site is shuttling electrons from the substrate to the trinuclear copper cluster. During the catalytic cycle of laccase, four electrons are removed from four substrate molecules, which are finally transferred to reduce oxygen to two water molecules .Comparison of the kinetic parameters using several laccases and several substrates reveals that the reaction rate of laccase correlates with the redox potential difference between the T1 copper and the substrate. In recent years, the demonstrated potential of laccases in a range of applications has motivated the progress of laccase engineering efforts. Computational simulations can reveal t...
Laccase from prokaryotes: a new source for an old enzyme
Reviews in Environmental Science and Bio/Technology, 2011
Laccases (benzenediol: oxygen oxidoreductase, EC 1.10.3.2) are multi-copper-containing enzymes capable of catalyzing the oxidation of a wide range of phenolic and non phenolic aromatic compounds. The available data indicates that laccases from prokaryotes are promising biological tools for green chemistry based applications, especially in decolorization of industrial textile dye effluents which constitute a major threat to soil and ground water reservoirs worldwide. Another appropriate application of prokaryotic laccases is bio-bleaching of different kind of pulps where there is indiscriminate use of hazardous chlorine based chemicals for brightness of the paper. In recent years, researchers have shown interest in the identification and characterization of laccases from prokaryotic sources. This catalyst is not commonly reported from this kingdom, although prokaryotes have immense environmental adaptability and biochemical versatility. Moreover, true laccases or laccase-like enzymes exist in many gram-negative, gram-positive bacteria and actinomycetes. Corresponding genes have been identified and functionally expressed in genetically developed hosts. This review summarizes the research efforts to characterize laccases and their properties from different prokaryotic sources, including bacteria and actinomycetes.
Molecules
Laccase, one of the metalloproteins, belongs to the multicopper oxidase family. It oxidizes a wide range of substrates and generates water as a sole by-product. The engineering of laccase is important to broaden their industrial and environmental applications. The general assumption is that the low redox potential of laccases is the principal obstacle, as evidenced by their low activity towards certain substrates. Therefore, the primary goal of engineering laccases is to improve their oxidation capability, thereby increasing their redox potential. Even though some of the determinants of laccase are known, it is still not entirely clear how to enhance its redox potential. However, the laccase active site has additional characteristics that regulate the enzymes’ activity and specificity. These include the electrostatic and hydrophobic environment of the substrate binding pocket, the steric effect at the substrate binding site, and the orientation of the binding substrate with respect ...
Structural and Functional Roles of Glycosylation in Fungal Laccase from Lentinus sp
PloS one, 2015
Laccases are multi-copper oxidases that catalyze the oxidation of various organic and inorganic compounds by reducing O2 to water. Here we report the crystal structure at 1.8 Å resolution of a native laccase (designated nLcc4) isolated from a white-rot fungus Lentinus sp. nLcc4 is composed of three cupredoxin-like domains D1-D3 each folded into a Greek key β-barrel topology. T1 and T2/T3 copper binding sites and three N-glycosylated sites at Asn75, Asn238, and Asn458 were elucidated. Initial rate kinetic analysis revealed that the kcat, Km, and kcat/Km of nLcc4 with substrate ABTS were 3,382 s-1, 65.0 ± 6.5 μM, and 52 s-1μM-1, respectively; and the values with lignosulfonic acid determined using isothermal titration calorimetry were 0.234 s-1, 56.7 ± 3.2 μM, and 0.004 s-1μM-1, respectively. Endo H-deglycosylated nLcc4 (dLcc4), with only one GlcNAc residue remaining at each of the three N-glycosylation sites in the enzyme, exhibited similar kinetic efficiency and thermal stability to...