L-Glutamine-, peptidyl- and protein-glutaminases: structural features and applications in the food industry.

L-Glutaminases are enzymes that catalyze the cleavage of the gamma-amido bond of L-glutamine residues, producing ammonia and L-glutamate. These enzymes have several applications in food and pharmaceutical industries. However, the L-glutaminases that hydrolyze free L-glutamine (L-glutamine glutaminases, EC 3.

Mycofumigation of postharvest blueberries with volatile compounds from Trichoderma atroviride IC-11 is a promising tool to control rots caused by Botrytis cinerea.

Botrytis cinerea, the causal agent of the gray mold, is a filamentous fungus that infects blueberries and can cause important production losses in postharvest storage. Considering that the use of synthetic fungicides is not allowed on blueberries in postharvest conditions, alternative and natural strategies are needed to control gray mold. The objective of this work was to evaluate the capability of volatile organic compounds (VOCs) produced by Trichoderma atroviride IC-11 to control B.

Characteristics of a Cold-Adapted L-glutaminase with Potential Applications in the Food Industry.

L-glutaminases are enzymes that catalyze the hydrolysis of L-glutamine, producing L-glutamate and ammonium, and they have promising applications in pharmaceutical and food industries. Several investigations have focused on thermo-tolerant L-glutaminases; however, studies on cold-adapted L-glutaminases have not been reported. These enzymes could be useful in the food industry because they display high catalytic activity at low and room temperatures, a valuable feature in processes aimed to save energy.

Trichoderma as biological control agent: scope and prospects to improve efficacy.

A major current challenge is to increase the food production while preserving natural resources. Agricultural practices that enhance the productivity and progressively improve the soil quality are relevant to face this challenge. Trichoderma species are widely used in agriculture to stimulate the plant growth and to control different pathogens affecting crops, representing useful tools for sustainable food production.

Prospecting Biotechnologically-Relevant Monooxygenases from Cold Sediment Metagenomes: An In Silico Approach.

The goal of this work was to identify sequences encoding monooxygenase biocatalysts with novel features by in silico mining an assembled metagenomic dataset of polar and subpolar marine sediments. The targeted enzyme sequences were Baeyer-Villiger and bacterial cytochrome P450 monooxygenases (CYP153). These enzymes have wide-ranging applications, from the synthesis of steroids, antibiotics, mycotoxins and pheromones to the synthesis of monomers for polymerization and anticancer precursors, due to their extraordinary enantio-, regio-, and chemo- selectivity that are valuable features for organic synthesis.

Metagenomics unveils the attributes of the alginolytic guilds of sediments from four distant cold coastal environments.

Alginates are abundant polysaccharides in brown algae that constitute an important energy source for marine heterotrophic bacteria. Despite the key role of alginate degradation processes in the marine carbon cycle, little information is available on the bacterial populations involved in these processes. The aim of this work was to gain a better understanding of alginate utilization capabilities in cold coastal environments.

Evaluating the role of conserved amino acids in bacterial O-oligosaccharyltransferases by in vivo, in vitro and limited proteolysis assays.

Bacterial O-Oligosaccharyltransferases (O-OTases) constitute a growing family of enzymes that catalyze the transfer of a glycan from a lipid carrier to protein acceptors. O-OTases are inner membrane proteins that display limited sequence similarity, except for the Wzy_C signature domain also present in a predicted periplasmic loop of the WaaL ligase, the enzyme responsible for transferring the O antigen to the lipid A core. The mechanism of O-OTase-dependent glycosylation is poorly understood.

In vitro glycosylation assay for bacterial oligosaccharyltransferases.

Oligosaccharyltransferases (OTases) constitute a family of glycosyltransferases that catalyze the transfer of an oligosaccharide from a lipid donor to an acceptor molecule, commonly a protein. These enzymes can transfer a variety of glycan structures, including polysaccharides, to different protein acceptors. Therefore, this property endows the OTases with great biotechnological potential as these enzymes could be applied to produce several glycoconjugates relevant to the pharmaceutical industry.

In vitro activity of Neisseria meningitidis PglL O-oligosaccharyltransferase with diverse synthetic lipid donors and a UDP-activated sugar.

Oligosaccharyltransferases (OTases) are enzymes that catalyze the transfer of an oligosaccharide from a lipid carrier to an acceptor molecule, commonly a protein. OTases are classified as N-OTases and O-OTases, depending on the nature of the glycosylation reaction. The N-OTases catalyze the glycan transfer to amide groups in asparagines in a reaction named N-linked glycosylation.

Structural backgrounds for the formation of a catalytically competent complex with NADP(H) during hydride transfer in ferredoxin-NADP(+) reductases.

The role of the highly conserved C266 and L268 of pea ferredoxin-NADP(+) reductase (FNR) in formation of the catalytically competent complex of the enzyme with NADP(H) was investigated. Previous studies suggest that the volume of these side-chains, situated facing the side of the C-terminal Y308 catalytic residue not stacking the flavin isoalloxazine ring, may be directly involved in the fine-tuning of the catalytic efficiency of the enzyme. Wild-type pea FNR as well as single and double mutants of C266 and L268 residues were analysed by fast transient-kinetic techniques and their midpoint reduction potentials were determined.

Structural-functional characterization and physiological significance of ferredoxin-NADP reductase from Xanthomonas axonopodis pv. citri.

Xanthomonas axonopodis pv. citri is a phytopathogen bacterium that causes severe citrus canker disease. Similar to other phytopathogens, after infection by this bacterium, plants trigger a defense mechanism that produces reactive oxygen species.

A highly stable plastidic-type ferredoxin-NADP(H) reductase in the pathogenic bacterium Leptospira interrogans.

Leptospira interrogans is a bacterium that is capable of infecting animals and humans, and its infection causes leptospirosis with a range of symptoms from flu-like to severe illness and death. Despite being a bacteria, Leptospira interrogans contains a plastidic class ferredoxin-NADP(H) reductase (FNR) with high catalytic efficiency, at difference from the bacterial class FNRs. These flavoenzymes catalyze the electron transfer between NADP(H) and ferredoxins or flavodoxins.

Swapping FAD binding motifs between plastidic and bacterial ferredoxin-NADP(H) reductases.

Plant-type ferredoxin-NADP(H) reductases (FNRs) are grouped in two classes, plastidic with an extended FAD conformation and high catalytic rates and bacterial with a folded flavin nucleotide and low turnover rates. The 112-123 β-hairpin from a plastidic FNR and the carboxy-terminal tryptophan of a bacterial FNR, suggested to be responsible for the FAD differential conformation, were mutually exchanged. The plastidic FNR lacking the β-hairpin was unable to fold properly.

Induced fit and equilibrium dynamics for high catalytic efficiency in ferredoxin-NADP(H) reductases.

Ferredoxin-NADP(H) reductase (FNR) is a FAD-containing protein that catalyzes the reversible transfer of electrons between NADP(H) and ferredoxin or flavodoxin. This enzyme participates in the redox-based metabolism of plastids, mitochondria, and bacteria. Plastidic plant-type FNRs are very efficient reductases in supporting photosynthesis.

Modulation of the enzymatic efficiency of ferredoxin-NADP(H) reductase by the amino acid volume around the catalytic site.

Ferredoxin (flavodoxin)-NADP(H) reductases (FNRs) are ubiquitous flavoenzymes that deliver NADPH or low-potential one-electron donors (ferredoxin, flavodoxin, adrenodoxin) to redox-based metabolic reactions in plastids, mitochondria and bacteria. Plastidic FNRs are quite efficient reductases. In contrast, FNRs from organisms possessing a heterotrophic metabolism or anoxygenic photosynthesis display turnover numbers 20- to 100-fold lower than those of their plastidic and cyanobacterial counterparts.