Characterization of the endo-β-1,3-glucanase activity of S. cerevisiae Eng2 and other members of the GH81 family

Martín-Cuadrado, Ana-Belén; Fontaine, Thierry; Esteban, Pedro F.; Dedo, Javier Encinar del; Medina-Redondo, María de; Rey, Francisco del; Latgé, Jean Paul; Aldana, Carlos R. Vázquez de

doi:10.1016/j.fgb.2007.09.001

Cited by 47 publications

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References 46 publications

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“…pombe contains two proteins belonging to the GH81 family encoded by the eng1 ϩ and eng2 ϩ genes. Both proteins have been shown to have endo-glucanase activity, specifically hydrolyzing ␤-1,3-glucan chains (25), like most of the members of this family described so far (4,11,12,31). Even though they display the same enzymatic activity, Eng1 and Eng2 function at different moments of the life cycle of fission yeast.…”

Section: Discussionmentioning

confidence: 96%

“…Previously, we have shown that Eng2 is a glucanase with high specificity for ␤-1,3-glucans, acting with an endohydrolytic mode of action (25). To analyze whether the increase in Eng2 protein levels during sporulation might result in an increase in ␤-1,3-glucanase activity, the activity of sporulating cells was assayed using laminarin as a substrate.…”

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confidence: 99%

“…1B). Since S. pombe contains two proteins belonging to the GH81 family encoded by the eng1 ϩ and eng2 ϩ genes (23,25), homozygous eng2⌬/eng2⌬ and eng1⌬/ eng1⌬ diploids were constructed to confirm that the increase in ␤-1,3-glucanase activity during sporulation was indeed due to eng2 ϩ . We observed that the basal level of ␤-1,3-glucanase activity of the eng2⌬/eng2⌬ strain did not increase along sporulation, which can be attributed to the activity of the Eng1 glucanase ( Fig.…”

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confidence: 99%

“…GH81 proteins share a conserved region of around 650 amino acids in which the catalytic domain is included (25). Within this domain, two perfectly conserved Glu residues (E550 or E554) have been proposed as putative nucleophiles of the active site of the Aspergillus fumigatus Engl1 endoglucanase, while the proton donor would be D475 (31).…”

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confidence: 99%

“…Within this domain, two perfectly conserved Glu residues (E550 or E554) have been proposed as putative nucleophiles of the active site of the Aspergillus fumigatus Engl1 endoglucanase, while the proton donor would be D475 (31). These conserved residues are also required for the activity of S. cerevisiae Eng2 and soybean glucan-binding elicitor protein, since point mutations abolish catalytic activity without affecting protein levels (10,25). To test whether hydrolysis of the ascus wall requires the enzymatic activity of Eng2, a point mutant in which one of the conserved Glu residues had been replaced by Ala was constructed [eng2(E537A) allele] (Fig.…”

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β-Glucanase Eng2 Is Required for Ascus Wall Endolysis after Sporulation in the Fission Yeast Schizosaccharomyces pombe

et al. 2009

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Meiosis is the developmental program by which sexually reproducing diploid organisms generate haploid gametes. In yeast, meiosis is followed by spore morphogenesis. When Schizosaccharomyces pombe diploid cells undergo meiosis, they differentiate into asci containing four haploid ascospores that are highly resistant to environmental stress. The formation of the ascospore wall requires the activity of several enzymes involved in the biosynthesis and modification of its components, such as ␣-and ␤-glucan synthases. Once the spores are completely mature, the wall of the ascus undergoes an endolytic process that results in the release of ascospores from the ascus, allowing their dispersal into the environment. This process requires the activity of the endo-␣-1,3-glucanase Agn2. Here, we focus on the characterization of the endo-␤-1,3-glucanase Eng2, which is also required for ascospore release from the ascus. Although Eng2 is present during the mitotic cycle, the protein accumulates after meiosis II. The expression of eng2 ؉ is required for the efficient release of ascospores, as shown by placing eng2 ؉ under the control of a repressible promoter. Furthermore, a point mutation that destroys the catalytic activity of the protein results in a phenotype similar to that of the mutant strain. Finally, we demonstrate that exogenous addition of purified Eng2 releases the ascospores from asci generated by an eng2⌬ mutant. We propose that Eng2 would act together with Agn2 to completely hydrolyze the ascus wall, thereby assisting in the release of ascospores in S. pombe.Cells of the fission yeast Schizosaccharomyces pombe have a rod-like shape and grow at the poles. S. pombe cells are stable in the haploid state and proliferate asexually until there is a shortage of nutrients. When cells are starved, especially of nitrogen, a sexual development program is triggered, and hence, cells from the opposite mating types conjugate to form zygotes. These immediately undergo meiosis, giving rise to four haploid zygotic ascospores (34).Spore formation is a complex differentiation program in which two sequential processes, meiosis and ascospore formation, occur in a coordinate fashion. During meiosis, the recently formed diploid nucleus undergoes a round of DNA replication, followed by two successive nuclear divisions generating four haploid nuclei (34). The morphogenetic program that leads to the formation of ascospores starts during meiosis II, when the four spindle-pole bodies (SPBs) differentiate into a sporulation-specific shape and change into a multilayered structure (15). These modified SPBs serve as the nucleation points for the fusion of membrane vesicles, resulting in the formation of a double-membrane structure, known as the forespore membrane, which engulfs each nuclear lobe and isolates the four haploid nuclei (15,33,34). Following this, the cell wall of the ascospore is synthesized de novo within the lumen of the forespore membrane through the deposition of successive layers of cell wall material mediated by the action of s...

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Section: Discussionmentioning

confidence: 96%

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confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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β-Glucanase Eng2 Is Required for Ascus Wall Endolysis after Sporulation in the Fission Yeast Schizosaccharomyces pombe

et al. 2009

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Investigation of the simulated microgravity impact on heavy metal biosorption by Saccharomyces cerevisiae

Salavatifar,

Khosravi‐Darani

2024

Food Science & Nutrition

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Heavy metals are one of the most dangerous environmental pollutions, and their elimination is one of the health system's priorities. Microorganisms have been introduced as a safe absorber of such pollution and this ability is related to the characteristics of their surface layers. There are reports about some bacteria's increment of cell envelope thickness in space conditions. Therefore, this study investigated SMG effect on heavy metals biosorption using Saccharomyces (S.) cerevisiae. Furthermore, the stability of complex, isotherm, and kinetic absorption models has been investigated. The results showed that the SMG positively affected the biosorption of mercury (Hg) 97% and lead (Pb) 72.5% by S. cerevisiae. In contrast, it did not affect cadmium (Cd) and arsenic (As) biosorption. In gastrointestinal conditions, Hg, Cd, and As‐yeast complexes were stable, and their biosorption increased. In the case of the Pb‐yeast complex, in simulated gastric exposure, the binding decreased at first but increased again in simulated intestinal exposure in both SMG and normal gravity (NG). The metals' biosorption by yeast followed the pseudo‐second‐order kinetic and the Langmuir isotherm models for all metals (As) matched with Langmuir and Freundlich. The current research results demonstrate that microgravity provides desirable conditions for heavy metal biosorption by S. cerevisiae. Furthermore, the biosorbent–heavy metal complex remains stable after simulated gastrointestinal conditions. Altogether, the results of this study could be considered in detoxifying food and beverage industries and maintaining astronauts' health.

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Characterization of the endo-β-1,3-glucanase activity of S. cerevisiae Eng2 and other members of the GH81 family

Cited by 47 publications

References 46 publications

β-Glucanase Eng2 Is Required for Ascus Wall Endolysis after Sporulation in the Fission Yeast Schizosaccharomyces pombe

β-Glucanase Eng2 Is Required for Ascus Wall Endolysis after Sporulation in the Fission Yeast Schizosaccharomyces pombe

Investigation of the simulated microgravity impact on heavy metal biosorption by Saccharomyces cerevisiae

Current awareness on yeast

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