Publications by authors named "Livia R Manzine"

Glycoside hydrolase family 5 (GH5) encompasses enzymes with several different activities, including endo-1,4-β-mannosidases. These enzymes are involved in mannan degradation, and have a number of biotechnological applications, such as mannooligosaccharide prebiotics production, stain removal and dyes decolorization, to name a few. Despite the importance of GH5 enzymes, only a few members of subfamily 7 were structurally characterized.

View Article and Find Full Text PDF

Structural biology projects are highly dependent on the large-scale expression of soluble protein and, for this purpose, heterologous expression using bacteria or yeast as host systems is usually employed. In this scenario, some of the parameters to be optimized include (i) those related to the protein construct, such as the use of a fusion protein, the choice of an N-terminus fusion/tag or a C-terminus fusion/tag; (ii) those related to the expression stage, such as the concentration and selection of inducer agent and temperature expression and (iii) the choice of the host system, which includes the selection of a prokaryotic or eukaryotic cell and the adoption of a strain. The optimization of some of the parameters related to protein expression, stage (ii), is straightforward.

View Article and Find Full Text PDF

A glycoside hydrolase family 5 (GH5) subfamily 22 gene, designated T81Xyl5_22A, was identified in the genome of the aerobic thermophilic bacterium, Thermogemmatispora sp. T81 (locus A4R35_07040). The gene was cloned and heterologously expressed in Escherichia coli and the gene product characterized biochemically.

View Article and Find Full Text PDF

Cellulases are essential enzymatic components for the transformation of plant biomass into fuels, renewable materials and green chemicals. Here, we determined the crystal structure, pattern of hydrolysis products release, and conducted molecular dynamics simulations of the major endoglucanase from the Xanthomonas campestris pv. campestris (XccCel5A).

View Article and Find Full Text PDF

Bifidobacterium is an important genus of probiotic bacteria colonizing the human gut. These bacteria can uptake oligosaccharides for the fermentative metabolism of hexoses and pentoses, producing lactate, acetate as well as short-chain fatty acids and propionate. These end-products are known to have important effects on human health.

View Article and Find Full Text PDF

Economic sustainability of modern biochemical technologies for plant cell wall transformations in renewable fuels, green chemicals, and sustainable materials is considerably impacted by the elevated cost of enzymes. Therefore, there is a significant drive toward discovery and characterization of novel carbohydrate-active enzymes. Here, the BlCel48 cellulase from Bacillus licheniformis, a glycoside hydrolase family 48 member (GH48), was functionally and biochemically characterized.

View Article and Find Full Text PDF

β-glucosidases are glycoside hydrolases able to cleave small and soluble substrates, thus producing monosaccharides. These enzymes are distributed among families GH1, GH2, GH3, GH5, GH9, GH30 and GH116, with GH1 and GH3 being the most relevant families with characterized enzymes to date. A recent transcriptomic analysis of the fungus Trichoderma harzianum, known for its increased β-glucosidase activity as compared to Trichoderma reesei, revealed two enzymes from family GH1 with high expression levels.

View Article and Find Full Text PDF

Endoglucanases are the main cellulolytic enzymes secreted by the bacterium Xanthomonas campestris pv. campestris (Xcc). The major endoglucanase exported by this bacterium into an external milieu is an enzyme XccCel5A, which belongs to GH5 family subfamily 1 and is encoded by the gene engXCA.

View Article and Find Full Text PDF

The synthesis of selenocysteine-containing proteins (selenoproteins) involves the interaction of selenocysteine synthase (SelA), tRNA (tRNA(Sec)), selenophosphate synthetase (SelD, SPS), a specific elongation factor (SelB), and a specific mRNA sequence known as selenocysteine insertion sequence (SECIS). Because selenium compounds are highly toxic in the cellular environment, the association of selenium with proteins throughout its metabolism is essential for cell survival. In this study, we demonstrate the interaction of SPS with the SelA-tRNA(Sec) complex, resulting in a 1.

View Article and Find Full Text PDF

Leishmania RNA Virus (LRV, Totiviridae) infect Leishmania cells and subvert mice immune response, probably promoting parasite persistence, suggesting significant roles for LRV in host-parasite interaction. Here we describe a new LRV1-4 purification protocol, enabling capsid visualization by negatively stained electron microscopy representing a significant contribution to future LRV investigations.

View Article and Find Full Text PDF

In bacteria selenocysteyl-tRNA(sec) (SelC) is synthesized by selenocysteine synthase (SelA). Here we show by fluorescence anisotropy binding assays and electron microscopical symmetry analysis that the SelA-tRNA(sec) binding stoichiometry is of one tRNA(sec) molecule per SelA monomer (1:1) rather than the 1:2 value proposed previously. Negative stain transmission electron microscopy revealed a D5 pointgroup symmetry for the SelA-tRNA(sec) assembly both with and without tRNA(sec) bound.

View Article and Find Full Text PDF

Because of its elevated cellulolytic activity, the filamentous fungus Trichoderma harzianum has a considerable potential in biomass hydrolysis applications. Trichoderma harzianum cellobiohydrolase I (ThCBHI), an exoglucanase, is an important enzyme in the process of cellulose degradation. Here, we report an easy single-step ion-exchange chromatographic method for purification of ThCBHI and its initial biophysical and biochemical characterization.

View Article and Find Full Text PDF