The extracellular system of β-1,3-glucanases ofAlternaria tenuissima andAspergillus vesicolor

Jirků, V.; Kraxnerová, B.; Krumphanzl, V.

doi:10.1007/bf02876394

Cited by 14 publications

(8 citation statements)

References 15 publications

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“…This structure was determined at 1.74 Å resolution. The ctab molecule, previously found to be an inhibitor of Lam (30), was located at the cleft of the active site, as shown in Fig. 2 (B and C).…”

Section: Tmlamcd Structures In Three Crystalmentioning

confidence: 76%

Crystal Structures of the Laminarinase Catalytic Domain from Thermotoga maritima MSB8 in Complex with Inhibitors

Jeng

Wang

Lin

et al. 2011

Journal of Biological Chemistry

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Laminarinases hydrolyzing the ␤-1,3-linkage of glucans play essential roles in microbial saccharide degradation. Here we report the crystal structures at 1.65-1.82 Å resolution of the catalytic domain of laminarinase from the thermophile Thermotoga maritima with various space groups in the ligand-free form or in the presence of inhibitors gluconolactone and cetyltrimethylammonium. Ligands were bound at the cleft of the active site near an enclosure formed by Trp-232 and a flexible GASIG loop. A closed configuration at the active site cleft was observed in some molecules. The loop flexibility in the enzyme may contribute to the regulation of endo-or exo-activity of the enzyme and a preference to release laminaritrioses in long chain carbohydrate hydrolysis. Glu-137 and Glu-132 are proposed to serve as the proton donor and nucleophile, respectively, in the retaining catalysis of hydrolyzation. Calcium ions in the crystallization media are found to accelerate crystal growth. Comparison of laminarinase and endoglucanase structures revealed the subtle difference of key residues in the active site for the selection of ␤-1,3-glucan and ␤-1,4-glucan substrates, respectively. Arg-85 may be pivotal to ␤-1,3-glucan substrate selection. The similarity of the structures between the laminarinase catalytic domain and its carbohydrate-binding modules may have evolutionary relevance because of the similarities in their folds.Thermotoga maritima is a hyperthermophilic, anaerobic, and fermentive saccharolytic bacterium, catabolizing sugars and its polymers to make energy. Laminarinase (3-␤-D-glucan glucanohydrolase; EC 3.2.1.39, Lam), 3 an endoglucosidase, hydrolyzes internal ␤-1,3-glucosyl linkages in ␤-D-glucans and is therefore crucial in carbohydrate degradation for nutrient uptake and energy production in bacteria. According to the sequenced genome of T. maritima MSB8 (1), the laminarinase gene encodes the enzyme composed of a catalytic domain and two carbohydrate-binding modules (CBMs) connected by a linker region on each terminus. The structure of TmLamCBM2, located on the C terminus, has previously been determined by Boraston et al. (2). The coexistence of CBM with catalytic domains is widespread in many modular bacterial polysaccharide hydrolases that contain separately folding modules (3). The prevalent role of CBMs is to facilitate the association of substrates with the catalytic module; moreover, they sometime boost the reaction efficiency of the catalytic domain (4, 5). The modularity in biological macromolecules draws scientists' attention in biocatalyst designs (6). Because of the substrate diversity among glycosyl hydrolases (GHs), it is not easy to classify these enzymes according to their substrate specificity. Henrissat and Bairoch (7) developed a sequence similarity-based classification to categorize GH enzymes as an alternative to the traditional enzyme classification system. Except for a laminaripentaose-producing ␤-1,3-glucanase from Streptomyces matensis, which belongs to GH-64 (8), most of the bacterial la...

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Section: Tmlamcd Structures In Three Crystalmentioning

confidence: 76%

Crystal Structures of the Laminarinase Catalytic Domain from Thermotoga maritima MSB8 in Complex with Inhibitors

Jeng

Wang

Lin

et al. 2011

Journal of Biological Chemistry

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“…Although most fungal p-glucanases have an optimum pH between pH 4-6 (Pitson et al, 1993), few 1,3-/J-glucanases from filamentous fungi like the one of A. ,fcrnzigatirs have a neutral optimal pH (Jirku et al, 1980;Bodenmann et al, 1985) and are stable at basic pH (pH 8-10; Tsujisaka et al, 1981;Iwamuro et al, 1985). Temperature optimum and stability of other glucanases are similar to the A. jiunzigatus endo-1,3-P-glucanase (Pitson et al.…”

Section: Discussionmentioning

confidence: 99%

Purification and Characterization of an Endo‐1,3‐β‐Glucanase from Aspergillus fumigatus

Fontaine

Hartland

Beauvais

et al. 1997

European Journal of Biochemistry

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An endo-I ,3-p-glucanase was purified from a cell wall autolysate of Aspcvgillus ,fumigatus. This pglucanase activity was associated with a glycosylated 74-kDa protein. Using a sensitive colorimetric assay and a high-performance anion-exchange chromatography with a pulsed electrochemical detector for product analysis, it was shown that the endoglucanase hydrolysed exclusively linear 1,3-P-glucan chains, had an optimum pH of 7.0 and an optimum temperature of 60°C. A substrate kinetic study gave a K,, value of 0.3 mg/ml for soluble (laminarin and laminari-oligosaccharides) and 1 .18 mg/ml for insoluble (curdlan) 1,3-P-glucan. Laminar-oligosaccharide degradation, analysed by HPLC, showed that the endoglucanase bind to the subtrate at several positions and suggested that the active site of the enzyme recognized five glucose units linked by a 1,3-1 bond. The association of the present endo-1,3-P-glucanase with the cell wall of A. fumigatus suggests a putative role for this enzyme during cell-wall morphogenesis.Keywords: endo-I ,3-P-glucanase ; cell wall : Aspergillus furnigutus; filamentous fungus.1 ,3-P-Glucanases are classified as exo-l,3-/$glucanase (1,3-P-glucan glucohydrolase) and endo-1,3-P-glucanase (1,3-1-glucan glucanohydrolase). Endoglucanase activities cleave inside a glucan chain in a more or less random fashion: while the exoglucanase activities release glucose residues from the non-reducing end. Many yeast and filamentous fungi produce both exocellular and cell-wall-associated exo-p-glucanases and endo-8-glucanases (Notario, 1982;Hien and Fleet, 1983 ;Copa-Patino, et al. 1989;Stahmann et al., 1993). 1,3-p-Glucan is a predominant polysaccharide of the fungal cell wall, and is thought to be responsible for the shape and rigidity of the wall (Cabib et al., 1982;Fleet, 1991). It has been suggested that 1,3-p-glucanase activities are essential to the continuous rearrangement of the wall 1,3-P-glucans during fungal growth (Cabib et al., 1988;Wessels, 1988). In the filamentous fungus Coprinus cinereus, endo-p-glucanases seem to play an essential role in stipe elongation (Kamada et al., 1985). In Sacchuronzyces cerevisiae, the production of exo-P-glucanases is growth-associated and cellcycle regulated (del Rey et al., 1979;Larriba et al., 1984;Jiang et al., 1995), suggesting that their activities are required at very specific stages during morphogenesis. For example, bud initiation, cell expansion, cell conjugation and sporulation are characterised by a higher activity of particular 1,3-~-glucanases (del Rey et al., 1982; Cenamor et al., 1987). However, gene disruption of yeast exo-p-glucanase activities does not modify the cellular growth (Larriba et al., 1995).Correspondence to T. Fontaine, lnstitut Pasteur, Laboratoire des Aspergillus, 25 rue du Docteur E. Roux, F-75724 Paris cedex 15, FranceAbbreviafions. Abz(OH)ONHNHZ, pamino-hydroxybenzoic acid hydrazide; Con-A, concanavalin A lcctin; dp, degree of polymerisation; Gn, oligosaccharide containing n 1,3-P-linked glucose residues ; G,,r, reduced oligosacchari...

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“…P-Glucan synthase enzymes are present in various Aspergillus spp., including A. nidulans (9), A. niger (18), A. vesicolor (6), and A. terreus (12). Both 1,3-p-glucanases (6,18) and 1,4-p-glucanases (8,18) and a-glucanases (8) have been identified in Aspergillus spp., but the a-glucanases may be involved only in conidiation and fructification (19). No published data have indicated any activity of cilofungin on Aspergillus spp., and for that reason, no data on the mechanism of action of cilofungin on aspergilli have been published.…”

Section: Discussionmentioning

confidence: 99%

Efficacy of cilofungin alone and in combination with amphotericin B in a murine model of disseminated aspergillosis

Denning

Stevens

1991

Antimicrob Agents Chemother

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Cilofungin, amphotericin B, and a combination of the two drugs were compared in a model of aspergillosis in immunocompetent mice in three experiments. Cilofungin was equivalent to amphotericin B in preventing death and eradicating cerebral aspergillosis, but it did not sterilize the kidneys. This is the first demonstration of the in vivo activity of cilofungin against any fungus other than Candida albicans. The mortality with combination therapy was higher than those with amphotericin B alone (P = 0.003) and cilofungin alone (P = 0.054), as was weight loss after infection, indicating antagonism between cilofungin and amphotericin B in this model. The mechanisms of action and antagonism remain to be explained.

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The extracellular system of β-1,3-glucanases ofAlternaria tenuissima andAspergillus vesicolor

Cited by 14 publications

References 15 publications

Crystal Structures of the Laminarinase Catalytic Domain from Thermotoga maritima MSB8 in Complex with Inhibitors

Crystal Structures of the Laminarinase Catalytic Domain from Thermotoga maritima MSB8 in Complex with Inhibitors

Purification and Characterization of an Endo‐1,3‐β‐Glucanase from Aspergillus fumigatus

Efficacy of cilofungin alone and in combination with amphotericin B in a murine model of disseminated aspergillosis

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