Structures of a glucose-tolerant β-glucosidase provide insights into its mechanism

Pang, Panjiao; Cao, Liping; Liu, Yuhuan; Xie, Wei; Wang, Zhong

doi:10.1016/j.jsb.2017.02.001

Cited by 30 publications

(18 citation statements)

References 40 publications

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“…In a more recent study, the comparison between crystallographic structures of tolerant and non-tolerant GH1 β-glucosidases has shown that the tolerant seems to have the region close to the AS prolonged on a kind of allosteric channel (AC), providing an alternative thermodynamically favorable binding site that is not the same as catalytic cleft [24]. Moreover, a computational approach detected mutations at the residue 228 and the AS/AC neighborhood from the metagenomic Bgl1B lead to structural signatures more similar to glucose tolerant β-glucosidases [25].…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Gives New Insights into the Glucose Tolerance and Inhibition Mechanisms on β-Glucosidases

et al. 2019

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β-Glucosidases are enzymes with high importance for many industrial processes, catalyzing the last and limiting step of the conversion of lignocellulosic material into fermentable sugars for biofuel production. However, β-glucosidases are inhibited by high concentrations of the product (glucose), which limits the biofuel production on an industrial scale. For this reason, the structural mechanisms of tolerance to product inhibition have been the target of several studies. In this study, we performed in silico experiments, such as molecular dynamics (MD) simulations, free energy landscape (FEL) estimate, Poisson–Boltzmann surface area (PBSA), and grid inhomogeneous solvation theory (GIST) seeking a better understanding of the glucose tolerance and inhibition mechanisms of a representative GH1 β-glucosidase and a GH3 one. Our results suggest that the hydrophobic residues Y180, W350, and F349, as well the polar one D238 act in a mechanism for glucose releasing, herein called “slingshot mechanism”, dependent also on an allosteric channel (AC). In addition, water activity modulation and the protein loop motions suggest that GH1 β-Glucosidases present an active site more adapted to glucose withdrawal than GH3, in consonance with the GH1s lower product inhibition. The results presented here provide directions on the understanding of the molecular mechanisms governing inhibition and tolerance to the product in β-glucosidases and can be useful for the rational design of optimized enzymes for industrial interests.

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Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Gives New Insights into the Glucose Tolerance and Inhibition Mechanisms on β-Glucosidases

et al. 2019

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“…Glucose inhibition (Figure 4C) is a common problem among β-glucosidases, [21,32] as the accumulation of the product of the hydrolytic process naturally reduces the catalytic efficiency of the enzyme. However, it has been reported that some βglucosidases belonging to the family GH1 can be exceptionally tolerant or even stimulated by glucose, but the mechanism of that tolerance/stimulation is still not clear.…”

Section: Activity Assaysmentioning

confidence: 99%

Release of Soybean Isoflavones by Using a β‐Glucosidase from Alicyclobacillus herbarius

et al. 2020

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β‐Glucosidases are used in the food industry to hydrolyse glycosidic bonds in complex sugars, with enzymes sourced from extremophiles better able to tolerate the process conditions. In this work, a novel β‐glycosidase from the acidophilic organism Alicyclobacillus herbarius was cloned and heterologously expressed in Escherichia coli BL21(DE3). AheGH1 was stable over a broad range of pH values (5–11) and temperatures (4–55 °C). The enzyme exhibited excellent tolerance to fructose and good tolerance to glucose, retaining 65 % activity in the presence of 10 % (w/v) glucose. It also tolerated organic solvents, some of which appeared to have a stimulating effect, in particular ethanol with a 1.7‐fold increase in activity at 10 % (v/v). The enzyme was then applied for the cleavage of isoflavone from isoflavone glucosides in an ethanolic extract of soy flour, to produce soy isoflavones, which constitute a valuable food supplement, full conversion was achieved within 15 min at 30 °C.

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“…TaBgl2 structure was observed to have the classical (α/β)8 triosephosphate isomerase (TIM) barrel fold. From this, an outer opening was created which the slot forms an active site cleft, with the catalytic motifs present opposite each other at the bottom of the active site, where a parallel β-barrel is formed from the β-sheets with α-helices located outside of the barrel [22,27,28]. Referring to Jeng et al [26] as the source of the template structure TrBgl2, comparisons were also made to β-glucosidases from bacterium Clostridium cellulovorans and termite Neotermes koshunensis.…”

Section: Secondary and Tertiary Structure Predictionsmentioning

confidence: 99%

In-Silico Characterization of Glycosyl Hydrolase Family 1 β-Glucosidase from Trichoderma asperellum UPM1

Sobri

Abd‐Aziz

Bakar

et al. 2020

IJMS

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β-glucosidases (Bgl) are widely utilized for releasing non-reducing terminal glucosyl residues. Nevertheless, feedback inhibition by glucose end product has limited its application. A noticeable exception has been found for β-glucosidases of the glycoside hydrolase (GH) family 1, which exhibit tolerance and even stimulation by glucose. In this study, using local isolate Trichoderma asperellum UPM1, the gene encoding β-glucosidase from GH family 1, hereafter designated as TaBgl2, was isolated and characterized via in-silico analyses. A comparison of enzyme activity was subsequently made by heterologous expression in Escherichia coli BL21(DE3). The presence of N-terminal signature, cis-peptide bonds, conserved active site motifs, non-proline cis peptide bonds, substrate binding, and a lone conserved stabilizing tryptophan (W) residue confirms the identity of Trichoderma sp. GH family 1 β-glucosidase isolated. Glucose tolerance was suggested by the presence of 14 of 22 known consensus residues, along with corresponding residues L167 and P172, crucial in the retention of the active site’s narrow cavity. Retention of 40% of relative hydrolytic activity on ρ-nitrophenyl-β-D-glucopyranoside (ρNPG) in a concentration of 0.2 M glucose was comparable to that of GH family 1 β-glucosidase (Cel1A) from Trichoderma reesei. This research thus underlines the potential in the prediction of enzymatic function, and of industrial importance, glucose tolerance of family 1 β-glucosidases following relevant in-silico analyses.

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Structures of a glucose-tolerant β-glucosidase provide insights into its mechanism

Cited by 30 publications

References 40 publications

Molecular Dynamics Gives New Insights into the Glucose Tolerance and Inhibition Mechanisms on β-Glucosidases

Molecular Dynamics Gives New Insights into the Glucose Tolerance and Inhibition Mechanisms on β-Glucosidases

Release of Soybean Isoflavones by Using a β‐Glucosidase from Alicyclobacillus herbarius

In-Silico Characterization of Glycosyl Hydrolase Family 1 β-Glucosidase from Trichoderma asperellum UPM1

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