Structural analysis and biochemical properties of laccase enzymes from two Pediococcus species

Abstract

Prokaryotic laccases are emergent biocatalysts. However, they have not been broadly found and characterized in bacterial organisms, especially in lactic acid bacteria. Recently, a prokaryotic laccase from the lactic acid bacterium Pediococcus acidilactici 5930, which can degrade biogenic amines, was discovered. Thus, our study aimed to shed light on laccases from lactic acid bacteria focusing on two Pediococcus laccases, P. acidilactici 5930 and Pediococcus pentosaceus 4816, which have provided valuable information on their biochemical activities on redox mediators and biogenic amines. Both laccases are able to oxidize canonical substrates as ABTS, ferrocyanide and 2,6-DMP, and non-conventional substrates as biogenic amines. With ABTS as a substrate, they prefer an acidic environment and show sigmoidal kinetic activity, and are rather thermostable. Moreover, this study has provided the first structural view of two lactic acid bacteria laccases, revealing new structural features not seen before in other well-studied laccases, but which seem characteristic for this group of bacteria. We believe that understanding the role of laccases in lactic acid bacteria will have an impact on their biotechnological applications and provide a framework for the development of engineered lactic acid bacteria with enhanced properties.

Food-grade expression of multicopper oxidase with improved capability in degrading biogenic amines

“…In comparison with the MCO from P. acidilactici, no degradation of histamine and putrescine was observed for this enzyme, although it showed less than 20% degradation of total BAs [31]. Other studies demonstrated only 10% and 5% degradation of histamine and putrescine by MCOs from LAB [32,57]. At present, the degradation rate of BAs using MCOs was lower than that using LAB strains [26], degradation of BAs by food-grade enzymes is still a promising method as the expression level of enzyme can be easily enhanced, and the catalytic efficiency of enzymes can be improved by various molecular modification strategies [58][59][60].…”

“…The gene encoding multicopper oxidase has been verified in the genome of Lactobacillus curvatus G-1, and this enzyme exhibits capability in degradation of six common BAs including histamine, tyramine, and putrescine [26]. MCO from Lactobacillus plantarum J16 can degrade tyramine, histamine, and putrescine, while the one from Pediococcus acidilactici CECT 5930 degrades tyramine only [27][28][29]. MCO from Lactobacillus fermentum Y29 showed activity against a broad range of substrates (histamine, tyramine, tryptamine, phenylethylamine, putrescine, cadaverine, and spermidine), and was found to be tolerant to 18% (w/v) NaCl [30].…”

Enzymatic Oxidation of Ca-Lignosulfonate and Kraft Lignin in Different Lignin-Laccase-Mediator-Systems and MDF Production

“…Another obvious difference in structure between asco-laccase MtL and basi-laccase CcLcc5 with possible negative regulatory effects on the enzymatic activity is the C-tail, which MtL has extra (Figure 1). Such C-tails are also typical of ascolaccases and act as a plug to block the water channel of the enzymes (Andberg et al, 2009;Pardo and Camarero, 2015;Ernst et al, 2018;Olmeda et al, 2021). It is conceivable that the function of the plug in asco-laccase MtL can be impaired by irregular structural effects caused by the hydrophilic Indulin AT.…”

Involvement of Laccase2 in Cuticle Sclerotization of the Whitefly, Bemisia tabaci Middle East–Asia Minor 1

“…2) is a dioxygen oxidoreductase that contains four copper atoms in the catalytic center. Laccases are widely distributed in fungi, higher plants, insects, and some bacteria [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ] and belong to the family of blue multi-copper oxidases (BMCOs) [ 8 , 9 , 10 ]. The wide range of substrates catalyzed by laccase contributes to the diversity of laccase function [ 11 ].…”