Showing papers by "Lígia O. Martins published in 2015"
TL;DR: 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.
Abstract: 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.
79 citations
TL;DR: The data point to the importance of the distal arginine in the catalytic mechanism of PpDyP, as also observed in DyPB from Rhodococcus jostii RHA1 but not in DyPs from the A and D subfamilies, which reinforces the idea of existence of mechanistic variations among members of the different sub-families of DyPs with direct implications for their enzymatic properties and potential for biotechnological applications.
43 citations
TL;DR: The obtained kinetic data suggest an important role of distal Asn in modulating the acid–base catalysis of BsDyP, which contributes to the establishment of structural determinants of DyPs that underlie their mechanistic properties and sheds more light on the subfamily-dependent features of these enzymes.
22 citations
01 Jan 2015
TL;DR: Rai et al. as mentioned in this paper showed that azo dyes, characterized by the presence of one or more azo groups (n=N), and anthraquinonic dyes represent the largest and most versatile groups.
Abstract: Synthetic dyes are xenobiotic compounds that are being increasingly used in several industries, with special emphasis in the paper, textile and leather industries. Over 100,000 commercial dyes exist today and more than 7 × 105 tons of dyestuff is produced annually, of which 1–1.5 × 105 tons is released into the wastewaters (Rai et al in Crit Rev Environ Sci Tecnhol 35:219–238, 2005). Among these, azo dyes, characterized by the presence of one or more azo groups (–N=N–), and anthraquinonic dyes represent the largest and most versatile groups.
22 citations
TL;DR: This work represents a new efficient and clean method to construct in one step C–C and C–N bonds in aromatic frameworks obtained using CotA laccase-catalysed oxidation of the meta,para-disubstituted arylamine 2,4-diaminophenyldiamine.
18 citations
TL;DR: A laboratory evolution approach was conducted to improve the specificity of the metallo-oxidase McoA from the hyperthermophilic bacterium Aquifex aeolicus for aromatic compounds, leading to the identification of the 2B3 variant featuring a 2-order of magnitude higher catalytic efficiency than the wild-type enzyme for the typical laccase substrate ABT.
Abstract: Multicopper oxidases are multifunctional enzymes that can be broadly divided into two functional classes: metallo-oxidases (with a robust activity toward metals, such as Cu+ or Fe2+) and laccases (with a superior catalytic efficiency for organic compounds). Laccases are green catalysts with an outstanding redox capability over a wide range of aromatic substrates using O2 as an electron acceptor and releasing water as reduced product. Hyperthermostable laccases are highly in demand for their robustness in biotechnological applications. In this study, a laboratory evolution approach was conducted to improve the specificity of the metallo-oxidase McoA from the hyperthermophilic bacterium Aquifex aeolicus for aromatic compounds. Four rounds of random mutagenesis of the mcoA-gene followed by high-throughput screening (∼94 000 clones) led to the identification of the 2B3 variant featuring a 2-order of magnitude higher catalytic efficiency (kcat/Km) than the wild-type enzyme for the typical laccase substrate ABT...
17 citations
TL;DR: The vibrational spectroscopic characterisation of a catalytic intermediate formed by the reaction of H2O2 with DyP-type peroxidase immobilised on a biocompatible coated metal support is reported.
Abstract: We report herein the vibrational spectroscopic characterisation of a catalytic intermediate formed by the reaction of H2O2 with DyP-type peroxidase immobilised on a biocompatible coated metal support. The SERR spectroscopic approach is of general applicability to other peroxidases which form relatively stable catalytic intermediates.
11 citations