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ABSTRACT A new gene from Bjerkandera adusta strain UAMH 8258 encoding a carbohydrate esterase (designated as BacesI) was isolated and expressed in Pichia pastoris. The gene had an open reading frame of 1410 bp encoding a polypeptide of 470 amino acid residues, the first 18 serving as a secretion signal peptide. Homology and phylogenetic analyses showed that BaCesI belongs to carbohydrate esterases family 4. Three-dimensional modeling of the protein and normal mode analysis revealed a breathing mode of the active site that could be relevant for esterase activity. Furthermore, the overall negative electrostatic potential of this enzyme suggests that it degrades neutral substrates and will not act on negative substrates such as peptidoglycan or p-nitrophenol derivatives. The enzyme shows a specific activity of 1.118 U mg−1 protein on 2-naphthyl acetate. No activity was detected on p-nitrophenol derivatives as proposed from the electrostatic potential data. The deacetylation activity of the recombinant BaCesI was confirmed by measuring the release of acetic acid from several substrates, including oat xylan, shrimp shell chitin, N-acetylglucosamine, and natural substrates such as sugar cane bagasse and grass. This makes the protein very interesting for the biofuels production industry from lignocellulosic materials and for the production of chitosan from chitin. Proteins 2015; 83:533-546. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Abstract: Laccases are important enzymes for bioremediation and the best-characterised are from the fungus Trametes versicolor. Here, we describe the cloning and characterisation of a new variant of laccase from T. versicolor and its expression in Saccharomyces cerevisiae. We have performed a sequence-based analysis of Trametes laccases that leads to a proposal for a new nomenclature of this fungus laccases according to their phylogenetic relationships since their nomenclature based on IPs is ambiguous. We also describe the kinetic properties of the recombinant enzyme. [Copyright &y& Elsevier]

A new gene from Bjerkandera adusta strain UAMH 8258 encoding a carbohydrate esterase (designated as BacesI) was isolated and expressed in Pichia pastoris. The gene had an open reading frame of 1410 bp encoding a polypeptide of 470 amino acid residues, the first 18 serving as a secretion signal peptide. Homology and phylogenetic analyses showed that BaCesI belongs to carbohydrate esterases family 4. Three-dimensional modeling of the protein and normal mode analysis revealed a breathing mode of the active site that could be relevant for esterase activity. Furthermore, the overall negative electrostatic potential of this enzyme suggests that it degrades neutral substrates and will not act on negative substrates such as peptidoglycan or p-nitrophenol derivatives. The enzyme shows a specific activity of 1.118 U mg(-1) protein on 2-naphthyl acetate. No activity was detected on p-nitrophenol derivatives as proposed from the electrostatic potential data. The deacetylation activity of the recombinant BaCesI was confirmed by measuring the release of acetic acid from several substrates, including oat xylan, shrimp shell chitin, N-acetylglucosamine, and natural substrates such as sugar cane bagasse and grass. This makes the protein very interesting for the biofuels production industry from lignocellulosic materials and for the production of chitosan from chitin., (© 2015 Wiley Periodicals, Inc.)

All living organisms are subject to changing environmental conditions, to which they must adapt in order to survive. Recently, there have been significant advances leading to the comprehension of the different mechanisms implicated in the responses to stressful situations in the yeast S. cerevisiae. In nature, as well as in laboratory conditions or industrial processes, this yeast is subjected to different adverse environmental situations, such as osmotic, thermal and oxidative stresses. A general stress response pathway, mediated by protein kinase A, allows S. cerevisiae to cope with these three stressful conditions. However, there are also specific response pathways that include the HOG kinase for osmotic stress, the Heat Shock Factor for thermal stress and Yap1p and Yap2p transcription factors that regulate the oxidative stress response, among other enzymatic and non-enzymatic mechanisms. In this review, we describe the perception and signal transduction pathways that regulate gene expression leading to the adaptation to most common types of stress in S. cerevisiae. We also include information regarding the interaction between the signal transduction pathways involved in the different responses that allow this organism to coordinate its various physiological processes for optimal adaptation to the changing environment.