Effect of cellobiose, glucose, ethanol, and metal ions on the cellulase enzyme complex of <i>Thermomonospora fusca</i>

Ferchak, John D.; Pye, Erica

doi:10.1002/bit.260251205

Cited by 50 publications

(19 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our results on Cu inhibition of endoglucanase may be explained by the fact that the protonation of the amino acids at the reactive site finally form a complex with metal ions [Geiger et al, 1999]. End-product (glucose and lactose) inhibition of CMCase was noticed in our present investigation and is supported by earlier reports [Ferchak and Pye, 1983;Xiao et al, 2004]. One similar study provides a solution of hemicellulose supplementation for the protection of this enzyme from end-product inhibition [Xiao et al, 2004].…”

Section: Discussionsupporting

confidence: 81%

“…Beside Cys modification, tryptophan might have been interfered by Hg [Clarke and Adams, 1987]. The endoglucanase inhibition by the Hg ion has been shown in different studies [Ferchak and Pye, 1983;Mandels and Reese, 1965], which is supported by a Cys mutation study [Ai et al, 2003]. The thiol groups can capture mercury, and thiolates (R-S-) and thioketones (R2-C = S) form a strong complex with Hg ions [Fuchs et al, 2006;Manceau and Nagy, 2008].…”

Section: Discussionmentioning

confidence: 78%

See 1 more Smart Citation

The Dual Carboxymethyl Cellulase and Gelatinase Activities of a Newly Isolated Protein from Brevibacillus agri ST15c10 Confer Reciprocal Regulations in Substrate Utilization

Maiti

Samanta²,

Sahoo³

et al. 2017

Microb Physiol

View full text Add to dashboard Cite

A protein showing endoglucanase-peptidase activity was prepared from a newly isolated bacterium (ST15c10). We identified ST15c10 as Brevibacillus agri based on electron-microscopic images and its 16S-rDNA sequence (GenBank accession No. HM446043), which exhibits 98.9% sequence identity to B. agri (KZ17)/B. formosus (DSM-9885T)/B. brevis. The enzyme was purified to homogeneity and gave a single peak during high-performance liquid chromatography on a Seralose 6B-150 gel-matrix/C-18 column. MALDI-TOF mass-spectrometry and bioinformatics studies revealed significant similarity to M42-aminopeptidases/endoglucanases of the CelM family. These enzymes are found in all Brevibacillus strains for which the genome sequence is known. ST15c10 grows optimally on carboxymethyl cellulose (CMC)-gelatin (40°C/pH 8-9), and also shows strong growth/carboxymethyl cellulase (CMCase) activity in submerged bagasse fermentation. The purified enzyme also functions as endoglucanase with solid bagasse/rice straw. Its CMCase activity (optimal at pH 5.6 and 60°C/K_m = 35.5 µM/V_max = 1,024U) was visualized by zymography on a CMC-polyacrylamide gel, which provided a strong band of approximately 70 kDa. The purified enzyme also showed strong peptidase (gelatinase) activity (pH 7.2/40°C during zymography on 6-12% gelatin/1% gelatin-PAGE (at approx. 70 kDa). The CMCase activity is inhibited by the metal ions Mn/Cu/Fe/Co (50%), Hg/KMnO₄ (100%), and by glucose or lactose (50-75%; all at 1 mM). The observed dose/time-dependent inhibition by Hg ions could be prevented with 2-mercaptoethanol. A comparison of the B. agri endoglucanase-aminopeptidase (ELK43520; 350 aa) with other members of the M42-family revealed the conservation of active-site residues Cys256/Cys260, which were previously identified as metal-binding sites. Regulation of the endoglucanase activity probably occurs via metal binding-triggered changes in the redox state of the enzyme. Studies on this type of enzyme are of high importance for basic scientific and industrial research.

show abstract

Section: Discussionsupporting

confidence: 81%

Section: Discussionmentioning

confidence: 78%

The Dual Carboxymethyl Cellulase and Gelatinase Activities of a Newly Isolated Protein from Brevibacillus agri ST15c10 Confer Reciprocal Regulations in Substrate Utilization

Maiti

Samanta²,

Sahoo³

et al. 2017

Microb Physiol

View full text Add to dashboard Cite

show abstract

“…In this study we showed that various oxidants [including Fe(II) and Cu(II)], whether as metal ions, organics, or metallo-organics, could inflict a significant inhibition of enzymatic cellulolysis (Tables 2 and 3). The inhibition of cellulase reactions by Fe(III), Cr(III), and KMnO 4 (a strong oxidant) was also reported previously (5,30,32,39). The inhibitory effect depended on the E o , the thermodynamic measure of oxidation potency, of the oxidants.…”

Section: Discussionsupporting

confidence: 74%

Inhibition of Cellulase-Catalyzed Lignocellulosic Hydrolysis by Iron and Oxidative Metal Ions and Complexes

Tejirian

2010

Appl Environ Microbiol

103

View full text Add to dashboard Cite

Enzymatic lignocellulose hydrolysis plays a key role in microbially driven carbon cycling and energy conversion and holds promise for bio-based energy and chemical industries. Cellulases (key lignocelluloseactive enzymes) are prone to interference from various noncellulosic substances (e.g., metal ions). During natural cellulolysis, these substances may arise from other microbial activities or abiotic events, and during industrial cellulolysis, they may be derived from biomass feedstocks or upstream treatments. Knowledge about cellulolysis-inhibiting reactions is of importance for the microbiology of natural biomass degradation and the development of biomass conversion technology. Different metal ions, including those native to microbial activity or employed for biomass pretreatments, are often tested for enzymatic cellulolysis. Only a few metal ions act as inhibitors of cellulases, which include ferrous and ferric ions as well as cupric ion. In this study, we showed inhibition by ferrous/ferric ions as part of a more general effect from oxidative (or redox-active) metal ions and their complexes. The correlation between inhibition and oxidation potential indicated the oxidative nature of the inhibition, and the dependence on air established the catalytic role that iron ions played in mediating the dioxygen inhibition of cellulolysis. Individual cellulases showed different susceptibilities to inhibition. It is likely that the inhibition exerted its effect more on cellulose than on cellulase. Strong iron ion chelators and polyethylene glycols could mitigate the inhibition. Potential microbiological and industrial implications of the observed effect of redox-active metal ions on enzymatic cellulolysis, as well as the prevention and mitigation of this effect in industrial biomass conversion, are discussed.

show abstract

“…It has been found that physiological concentrations of cellobiose can activate cellulase-related gene transcription (30). Glucose has been found to repress transcription of cellulase-related genes (30) and impair growth of T. fusca (31,32).…”

mentioning

confidence: 99%

Laboratory Evolution and Multi-platform Genome Re-sequencing of the Cellulolytic Actinobacterium Thermobifida fusca

Deng

Fong

2011

Journal of Biological Chemistry

View full text Add to dashboard Cite

Biological utilization of cellulose is a complex process involving the coordinated expression of different cellulases, often in a synergistic manner. One possible means of inducing an organism-level change in cellulase activity is to use laboratory adaptive evolution. In this study, evolved strains of the cellulolytic actinobacterium, Thermobifida fusca, were generated for two different scenarios: continuous exposure to cellobiose (strain muC) or alternating exposure to cellobiose and glucose (strain muS). These environmental conditions produced a phenotype specialized for growth on cellobiose (muC) and an adaptable, generalist phenotype (muS). Characterization of cellular phenotypes and whole genome re-sequencing were conducted for both the muC and muS strains. Phenotypically, the muC strain showed decreased cell yield over the course of evolution concurrent with decreased cellulase activity, increased intracellular ATP concentrations, and higher end-product secretions. The muS strain increased its cell yield for growth on glucose and exhibited a more generalist phenotype with higher cellulase activity and growth capabilities on different substrates. Whole genome re-sequencing identified 48 errors in the reference genome and 18 and 14 point mutations in the muC and muS strains, respectively. Among these mutations, the site mutation of Tfu_1867 was found to contribute the specialist phenotype and the site mutation of Tfu_0423 was found to contribute the generalist phenotype. By conducting and characterizing evolution experiments on Thermobifida fusca, we were able to show that evolutionary changes balance ATP energetic considerations with cellulase activity. Increased cellulase activity is achieved in stress environments (switching carbon sources), otherwise cellulase activity is minimized to conserve ATP.

show abstract

Effect of cellobiose, glucose, ethanol, and metal ions on the cellulase enzyme complex of Thermomonospora fusca

Cited by 50 publications

References 18 publications

The Dual Carboxymethyl Cellulase and Gelatinase Activities of a Newly Isolated Protein from Brevibacillus agri ST15c10 Confer Reciprocal Regulations in Substrate Utilization

The Dual Carboxymethyl Cellulase and Gelatinase Activities of a Newly Isolated Protein from Brevibacillus agri ST15c10 Confer Reciprocal Regulations in Substrate Utilization

Inhibition of Cellulase-Catalyzed Lignocellulosic Hydrolysis by Iron and Oxidative Metal Ions and Complexes

Laboratory Evolution and Multi-platform Genome Re-sequencing of the Cellulolytic Actinobacterium Thermobifida fusca

Contact Info

Product

Resources

About