1,721,036 research outputs found
Beyond natural laccases: extension of their potential applications by protein engineering
No full textLaccases bring exciting promises into the green industries, and the development of enzymes with improved properties is further raising their exploitation potential. Molecular engineering methods to build highly efficient catalysts both through rational and random mutagenesis were extensively applied. Moreover, computational approaches are becoming always more reliable in aiding proper design of efficient and tailored catalyst for specific applications. In this review, the results of the last 10 years about industrial application of engineered laccases in different fields are analyzed. Tailoring laccase towards a target substrate and defining a proper screening strategy for the selection of the “jackpot mutant” represent the keys of a winning mutagenesis pathway. Likewise, laccase chimerae, built by the fusion of laccases with relevant proteins, emerged as an added value in the designing of flexible and well-rounded biocatalysts. Despite being promising in most of the reported examples, evolved laccases are currently tested at a laboratory scale and a feedback from the industry world is continuously required to strengthen the biotechnological exploitation of these improved enzymes
Molecular characterization of a recombinant replication protein (Rep) from the Antarctic bacterium Psychrobacter sp. TA144.
No full textRecombinant expression of Pleurotus ostreatus laccases in Kluyveromyces lactis and Saccharomyces cerevisiae
Full text linkHeterologous expression of Pleurotus ostreatus POXC and POXA1b laccases in two yeasts, Kluyveromyces lactis and Saccharomyces cerevisiae, was performed. Both transformed hosts secreted recombinant active laccases, although K. lactis was much more effective than S. cerevisiae. rPOXA1b transformants always had higher secreted activity than rPOXC transformants did. The lower tendency of K. lactis with respect to S. cerevisiae to hyperglycosylate recombinant proteins was confirmed. Recombinant laccases from K. lactis were purified and characterised. Specific activities of native and recombinant POXA1b are similar. On the other hand, rPOXC specific activity is much lower than that of the native protein, perhaps due to incomplete or incorrect folding. Both recombinant laccase signal peptides were correctly cleaved, with rPOXA1b protein having two C-terminal amino acids removed. The availability of the established recombinant expression system provides better understanding of laccase structure-function relationships and allows the development of new oxidative catalysts through molecular evolution techniques
A rolling-circle plasmid from Psychrobacter sp. TA144: evidence for a novel rep subfamily.
No full textA rolling-circle plasmid from Psychrobacter sp. TA144: evidence for a novel rep subfamily.
No full textRecombinant expression of Toluene o-Xylene Monooxygenase (ToMO) from Pseudomonas stutzeri OX1 in the marine Antarctic bacterium Pseudoalteromonas haloplanktis TAC125
No full textThe psychrophilic bacterium Pseudoalteromonas haloplanktis TAC125, isolated from Antarctic seawater, was used as recipient for a biodegradative gene of the mesophilic Pseudomonas stutzeri OX1. tou cluster, coding for Toluene o-Xylene Monooxygenase (ToMO), was successfully cloned and expressed into a "cold expression" vector. Apparent catalytic parameters of the recombinant microorganisms on three different substrates were determined and compared with those exhibited by Escherichia coli recombinant cells expressing ToMO. Production of a catalytically efficient TAC/tou microorganism supports the possibility of developing specific degradative capabilities for the bioremediation of chemically contaminated marine environments and of industrial effluents characterised by low temperatures
A rolling-circle plasmid from Psychrobacter sp. TA144: evidence for a novel rep subfamily.
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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