Structural modeling and further improvement in pH stability and activity of a highly-active xylanase from an uncultured rumen fungus

Chen, Yo-Chia; Chiang, Yu-Chuan; Hsu, Fu-Yuan; Tsai, Li-Chu; Cheng, Hsueh‐Ling

doi:10.1016/j.biortech.2012.05.142

Cited by 19 publications

(7 citation statements)

References 23 publications

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“…Recent evidence confirmed that the helix−coil transition of polysaccharide was induced by heat treatment at about 130−145 °C because of the breakage of hydrogen bonds. 38 The primary structure may not be damaged under the selected temperatures, although a higher structure may likely contribute much to the biological activity of DP1; the primary structure of DP1 also maintained a considerable part of immune activity. The thermostability of DP1 was further analyzed using TGA.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

“…The reason for these results may be mainly because of the fact that thermal treatment just destroyed the higher structure (e.g., triple helical) of DP1. Recent evidence confirmed that the helix–coil transition of polysaccharide was induced by heat treatment at about 130–145 °C because of the breakage of hydrogen bonds . The primary structure may not be damaged under the selected temperatures, although a higher structure may likely contribute much to the biological activity of DP1; the primary structure of DP1 also maintained a considerable part of its immune activity.…”

Section: Results and Discussionmentioning

confidence: 99%

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Structure Characterization of a Novel Polysaccharide from Dictyophora indusiata and Its Macrophage Immunomodulatory Activities

Liao

Luo

Liu

et al. 2015

J. Agric. Food Chem.

193

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A novel polysaccharide, here named DP1, was isolated from the fruiting body of Dictyophora indusiata using a water extraction method. Structure characterization revealed that DP1 had an average molecular weight of 1132 kDa and consisted of glucose (56.2%), galactose (14.1%), and mannose (29.7%). The main linkage type of DP1 were proven to be (1 → 3)-linked α-l-Man, (1 → 2,6)-linked α-d-Glc, (1 → 6)-linked β-d-Glc, (1 → 6)-linked β-d-Gal, and (1 → 6)-linked β-d-Man by periodate oxidation-Smith degradation and nuclear magnetic resonance analysis. The immunostimulating assay indicated that DP1 could significantly promote macrophage NO, TNF-α, and IL-6 secretion in murine RAW 264.7 cells involving complement receptor 3 (CR3). The immune activities of DP1 were quite stable under thermal processing (100, 121, and 145 °C). Besides, DP1 retained stability after acidic/alkline treatment (pH 4.0-10.0), which enabled it to be an ideal complementary medicine or functional food for therapeutics of hypoimmunity and immunodeficiency diseases.

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Section: ■ Results and Discussionmentioning

confidence: 98%

Section: Results and Discussionmentioning

confidence: 99%

Structure Characterization of a Novel Polysaccharide from Dictyophora indusiata and Its Macrophage Immunomodulatory Activities

Liao

Luo

Liu

et al. 2015

J. Agric. Food Chem.

193

View full text Add to dashboard Cite

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“…Studies on the functional transfer of anaerobic fungal enzymes to tractable bioprocessing hosts, such as S. cerevisae and E. coli , are rapidly emerging (Chen et al, ; Comlekcioglu et al, ; O'Malley et al, ). So far, some enzymes have proved promising because they remain active at a wide pH range (Chen et al, ), suggesting that they may be sufficiently robust for industrial processes. On the other hand, some enzymes tested in these hosts yield low or undetectable activity (Harhangi et al, ; O'Malley et al, ), possibly due to the lack of post‐translational modifications required for their activity.…”

Section: Heterologous Production Of Gut Fungal Enzymes For Biofuel Prmentioning

confidence: 99%

Anaerobic gut fungi: Advances in isolation, culture, and cellulolytic enzyme discovery for biofuel production

Haitjema

Solomon

Henske

et al. 2014

Biotech & Bioengineering

113

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Anaerobic gut fungi are an early branching family of fungi that are commonly found in the digestive tract of ruminants and monogastric herbivores. It is becoming increasingly clear that they are the primary colonizers of ingested plant biomass, and that they significantly contribute to the decomposition of plant biomass into fermentable sugars. As such, anaerobic fungi harbor a rich reservoir of undiscovered cellulolytic enzymes and enzyme complexes that can potentially transform the conversion of lignocellulose into bioenergy products. Despite their unique evolutionary history and cellulolytic activity, few species have been isolated and studied in great detail. As a result, their life cycle, cellular physiology, genetics, and cellulolytic metabolism remain poorly understood compared to aerobic fungi. To help address this limitation, this review briefly summarizes the current body of knowledge pertaining to anaerobic fungal biology, and describes progress made in the isolation, cultivation, molecular characterization, and long-term preservation of these microbes. We also discuss recent cellulase- and cellulosome-discovery efforts from gut fungi, and how these interesting, non-model microbes could be further adapted for biotechnology applications.

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“…In many of these applications extremes of pH are encountered yet, interestingly, while much is already known of this important industrial enzyme, little is known of its relationship to pH and of the pH dependence of its activity and stability. In fact, GH8 also contains many other industrially important enzymes such as cellulases, licheninases and chitosanases yet it appears that, in contrast to family 10 and 11 enzymes where a large number of studies have been carried out [5,9,10,[22][23][24][25][26], pH adaptation in GH8 enzymes has not been studied. Furthermore, in contrast to adaptation of enzymes to temperature, and in particular high temperatures, much less is currently known of adaptation to pH, with variable and sometimes conflicting observations on adaptation strategies being reported [5,9,10,[22][23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Deciphering the factors defining the pH-dependence of a commercial glycoside hydrolase family 8 enzyme

Barroca

Santos

Johansson

et al. 2017

Enzyme and Microbial Technology

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A prerequisite to the use of any enzyme in any industrial process is an understanding of its activity and stability under process conditions. Glycoside hydrolase family 8 enzymes include many important biotechnological biocatalysts yet little is known of the performance of these with respect to pH. A better understanding of this parameter and its relationship to structure and function in these enzymes will allow for an improved use of these in industry as well as an enhanced ability in their engineering and optimisation for a particular application. An in-depth analysis of the pH induced changes in activity, irreversible inactivation, conformation, stability and solubility of a commercial glycoside hydrolase family 8 xylanase was carried out with the aim of identifying the factors determining the pH dependence of this enzyme. Our study showed that different phenomena play different roles at the various pHs examined. Both reversible and irreversible processes are involved at acidic pHs, with the irreversible processes dominating and being due to protein aggregation and precipitation. At basic pHs, loss of activity is principally due to reversible processes, possibly deprotonation of an essential catalytic residue, but at higher pHs, near the pI of the protein, precipitation again dominates while structure unfolding was discerned at the higher pHs investigated. Such insights demonstrate the complexity of factors involved in the pH dependence of proteins and advances our knowledge on design principles and concepts for engineering proteins. Our results highlight the major role of protein precipitation in activity and stability losses at both low and high pHs but it is proposed that different strategies be used in tailoring the enzyme to overcome this in each case. Indeed the detailed understanding obtained here will allow for a more focused, informed and hence successful tailoring of glycoside hydrolase family 8 proteins for a specific pH and process application.

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Structural modeling and further improvement in pH stability and activity of a highly-active xylanase from an uncultured rumen fungus

Cited by 19 publications

References 23 publications

Structure Characterization of a Novel Polysaccharide from Dictyophora indusiata and Its Macrophage Immunomodulatory Activities

Structure Characterization of a Novel Polysaccharide from Dictyophora indusiata and Its Macrophage Immunomodulatory Activities

Anaerobic gut fungi: Advances in isolation, culture, and cellulolytic enzyme discovery for biofuel production

Deciphering the factors defining the pH-dependence of a commercial glycoside hydrolase family 8 enzyme

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