scholarly journals Novel Bi-Modular GH19 Chitinase with Broad pH Stability from a Fibrolytic Intestinal Symbiont of Eisenia fetida, Cellulosimicrobium funkei HY-13

Biomolecules ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1735
Author(s):  
Lu Bai ◽  
Jonghoon Kim ◽  
Kwang-Hee Son ◽  
Chung-Wook Chung ◽  
Dong-Ha Shin ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Eisenia Fetida ◽  
Polymeric Materials ◽  
Degree Of Polymerization ◽  
Ph Stability ◽  
Glycoside Hydrolase Family ◽  
Metabolic Dysfunction ◽  
Chitin Binding Domain ◽  
Shrimp Shell ◽  
Wide Ph Range

Endo-type chitinase is the principal enzyme involved in the breakdown of N-acetyl-d-glucosamine-based oligomeric and polymeric materials through hydrolysis. The gene (966-bp) encoding a novel endo-type chitinase (ChiJ), which is comprised of an N-terminal chitin-binding domain type 3 and a C-terminal catalytic glycoside hydrolase family 19 domain, was identified from a fibrolytic intestinal symbiont of the earthworm Eisenia fetida, Cellulosimicrobium funkei HY-13. The highest endochitinase activity of the recombinant enzyme (rChiJ: 30.0 kDa) toward colloidal shrimp shell chitin was found at pH 5.5 and 55 °C and was considerably stable in a wide pH range (3.5–11.0). The enzyme exhibited the highest biocatalytic activity (338.8 U/mg) toward ethylene glycol chitin, preferentially degrading chitin polymers in the following order: ethylene glycol chitin > colloidal shrimp shell chitin > colloidal crab shell chitin. The enzymatic hydrolysis of N-acetyl-β-d-chitooligosaccharides with a degree of polymerization from two to six and colloidal shrimp shell chitin yielded primarily N,N′-diacetyl-β-d-chitobiose together with a small amount of N-acetyl-d-glucosamine. The high chitin-degrading ability of inverting rChiJ with broad pH stability suggests that it can be exploited as a suitable biocatalyst for the preparation of N,N′-diacetyl-β-d-chitobiose, which has been shown to alleviate metabolic dysfunction associated with type 2 diabetes.

scholarly journals The third chitinase gene (chiC) of Serratia marcescens 2170 and the relationship of its product to other bacterial chitinases

1999 ◽  
Vol 343 (3) ◽  
pp. 587-596 ◽  
Author(s):  
Kazushi SUZUKI ◽  
Mayumi TAIYOJI ◽  
Noriko SUGAWARA ◽  
Naoki NIKAIDOU ◽  
Bernard HENRISSAT ◽  
...  
Keyword(s):  
Serratia Marcescens ◽  
Catalytic Domain ◽  
Signal Sequence ◽  
Early Stage ◽  
Hydrolytic Activity ◽  
Chitinase Gene ◽  
Glycoside Hydrolase Family ◽  
Chitin Binding Domain ◽  
The Third ◽  
Fn3 Domain

The third chitinase gene (chiC) of Serratia marcescens 2170, specifying chitinases C1 and C2, was identified. Chitinase C1 lacks a signal sequence and consists of a catalytic domain belonging to glycoside hydrolase family 18, a fibronectin type III-like domain (Fn3 domain) and a C-terminal chitin-binding domain (ChBD). Chitinase C2 corresponds to the catalytic domain of C1 and is probably generated by proteolytic removal of the Fn3 and ChBDs. The loss of the C-terminal portion reduced the hydrolytic activity towards powdered chitin and regenerated chitin, but not towards colloidal chitin and glycol chitin, illustrating the importance of the ChBD for the efficient hydrolysis of crystalline chitin. Phylogenetic analysis showed that bacterial family 18 chitinases can be clustered in three subfamilies which have diverged at an early stage of bacterial chitinase evolution. Ser. marcescens chitinase C1 is found in one subfamily, whereas chitinases A and B of the same bacterium belong to another subfamily. Chitinase C1 is the only Ser. marcescens chitinase that has an Fn3 domain. The presence of multiple, divergent, chitinases in a single chitinolytic bacterium is perhaps necessary for efficient synergistic degradation of chitin.

Enhancement of Mechanical Properties Upon Hydration in Copolymers of PEG and Iodinated Tyrosine-derived Poycarbonates

2008 ◽  
Vol 1132 ◽  
Author(s):  
F. Bedoui ◽  
L. K. Widjaja ◽  
A. Luk ◽  
D. Bolikal ◽  
N. S. Murthy ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Ethylene Glycol ◽  
Ethyl Ester ◽  
Opposite Effect ◽  
Polymeric Materials ◽  
Cross Linking ◽  
Poly Ethylene Glycol ◽  
Reinforcing Effect ◽  
Poly Ethylene

ABSTRACTIncrease in modulus upon hydration in copolymers of desaminotyrosyl-tyrosine ethyl ester (DTE) and poly(ethylene glycol) (PEG) with iodinated tyrosines, poly(I2DTE-co-PEG carbonate)s, was investigated by varying the fraction and the molecular weight of the hydrophilic PEG component. Water, as expected, acts as plasticizer in polymer with PEG content < 15 wt% and > 30 wt%. But, water has the opposite effect in iodinated polymers with moderate PEG contents, between 15 to 20 wt%: it enhances the Young's modulus. The strength and modulus of hydrated poly(I2DTE-co-15%PEG2K carbonate)s increased by as much as fifteen fold upon hydration. While the decrease in the mechanical properties in most polymeric materials with diluents such water is due to the solvent-induced swelling, the increase in strength and modulus that is observed is most likely due to the reinforcing effect of the increased cross-linking efficiency of the hydrated PEG domains in the iodinated polymer.

scholarly journals Comparative Analyses of Two Thermophilic Enzymes Exhibiting both β-1,4 Mannosidic and β-1,4 Glucosidic Cleavage Activities from Caldanaerobius polysaccharolyticus

2010 ◽  
Vol 192 (16) ◽  
pp. 4111-4121 ◽  
Author(s):  
Yejun Han ◽  
Dylan Dodd ◽  
Charles W. Hespen ◽  
Samuel Ohene-Adjei ◽  
Charles M. Schroeder ◽  
...  
Keyword(s):  
Catalytic Domain ◽  
Biochemical Properties ◽  
Degree Of Polymerization ◽  
Glycoside Hydrolase Family ◽  
Carbohydrate Binding ◽  
Biofuel Industry ◽  
Carbohydrate Binding Modules ◽  
Mannanase Activity ◽  
Hydrolysis Of ◽  
Derivatives Of

ABSTRACT The hydrolysis of polysaccharides containing mannan requires endo-1,4-β-mannanase and 1,4-β-mannosidase activities. In the current report, the biochemical properties of two endo-β-1,4-mannanases (Man5A and Man5B) from Caldanaerobius polysaccharolyticus were studied. Man5A is composed of an N-terminal signal peptide (SP), a catalytic domain, two carbohydrate-binding modules (CBMs), and three surface layer homology (SLH) repeats, whereas Man5B lacks the SP, CBMs, and SLH repeats. To gain insights into how the two glycoside hydrolase family 5 (GH5) enzymes may aid the bacterium in energy acquisition and also the potential application of the two enzymes in the biofuel industry, two derivatives of Man5A (Man5A-TM1 [TM1 stands for truncational mutant 1], which lacks the SP and SLH repeats, and Man5A-TM2, which lacks the SP, CBMs, and SLH repeats) and the wild-type Man5B were biochemically analyzed. The Man5A derivatives displayed endo-1,4-β-mannanase and endo-1,4-β-glucanase activities and hydrolyzed oligosaccharides with a degree of polymerization (DP) of 4 or higher. Man5B exhibited endo-1,4-β-mannanase activity and little endo-1,4-β-glucanase activity; however, this enzyme also exhibited 1,4-β-mannosidase and cellodextrinase activities. Man5A-TM1, compared to either Man5A-TM2 or Man5B, had higher catalytic activity with soluble and insoluble polysaccharides, indicating that the CBMs enhance catalysis of Man5A. Furthermore, Man5A-TM1 acted synergistically with Man5B in the hydrolysis of β-mannan and carboxymethyl cellulose. The versatility of the two enzymes, therefore, makes them a resource for depolymerization of mannan-containing polysaccharides in the biofuel industry. Furthermore, on the basis of the biochemical and genomic data, a molecular mechanism for utilization of mannan-containing nutrients by C. polysaccharolyticus is proposed.

scholarly journals The structure of PfGH50B, an agarase from the marine bacterium Pseudoalteromonas fuliginea PS47

2020 ◽  
Vol 76 (9) ◽  
pp. 422-427
Author(s):  
Benjamin Pluvinage ◽  
Craig S. Robb ◽  
Roderick Jeffries ◽  
Alisdair B. Boraston
Keyword(s):  
Glycoside Hydrolase ◽  
Marine Bacterium ◽  
Structural Features ◽  
Degree Of Polymerization ◽  
Glycoside Hydrolase Family ◽  
Carbohydrate Binding ◽  
X Ray ◽  
Terminal Domain ◽  
Polysaccharide Utilization Locus ◽  
Hydrolase Family

The recently identified marine bacterium Pseudoalteromonas fuliginea sp. PS47 possesses a polysaccharide-utilization locus dedicated to agarose degradation. In particular, it contains a gene (locus tag EU509_06755) encoding a β-agarase that belongs to glycoside hydrolase family 50 (GH50), PfGH50B. The 2.0 Å resolution X-ray crystal structure of PfGH50B reveals a rare complex multidomain fold that was found in two of the three previously determined GH50 structures. The structure comprises an N-terminal domain with a carbohydrate-binding module (CBM)-like fold fused to a C-terminal domain by a rigid linker. The CBM-like domain appears to function by extending the catalytic groove of the enzyme. Furthermore, the PfGH50B structure highlights key structural features in the mobile loops that may function to restrict the degree of polymerization of the neoagaro-oligosaccharide products and the enzyme processivity.

scholarly journals A novel bacterial β-N-acetyl glucosaminidase from Chitinolyticbacter meiyuanensis possessing transglycosylation and reverse hydrolysis activities

2020 ◽  
Author(s):  
Alei Zhang ◽  
Xiaofang Mo ◽  
Ning Zhou ◽  
Yingying Wang ◽  
Guoguang Wei ◽  
...  
Keyword(s):  
Specific Activity ◽  
Biological Activities ◽  
Active Form ◽  
Degree Of Polymerization ◽  
Glycoside Hydrolase Family ◽  
The Novel ◽  
Gene Encoding ◽  
Transglycosylation Activity ◽  
Reverse Hydrolysis ◽  
Hydrolysis Activity

Abstract Background: N-acetyl glucosamine (GlcNAc) and N-acetyl chitooligosaccharides (N-acetyl COSs) exhibit many biological activities, and have been widely used in the pharmaceutical, agriculture, food, and chemical industries. Particularly, higher N-acetyl COSs with degree of polymerization from 4 to 7 ((GlcNAc)4−(GlcNAc)7) show good antitumor and antimicrobial activity, as well as possessing strong stimulating activity towards natural killer cells. Thus, it is of great significance to discover a β-N-acetyl glucosaminidase (NAGase) that can not only produce GlcNAc, but also synthesize N-acetyl COSs. Results: The gene encoding the novel β-N-acetyl glucosaminidase, designated CmNAGase, was cloned from Chitinolyticbacter meiyuanensis SYBC-H1. The deduced amino acid sequence of CmNAGase contains a glycoside hydrolase family 20 catalytic module that shows low identity (12−35%) with the corresponding domain of most well-characterized NAGases. The CmNAGase gene was highly expressed with an active form in Escherichia coli BL21 (DE3) cells. The specific activity of purified CmNAGase toward p-nitrophenyl-N-acetyl glucosaminide (pNP-GlcNAc) was 4,878.6 U/mg of protein. CmNAGase had a molecular mass of 92 kDa, and its optimum activity was at pH 5.4 and 40ºC. The Vmax, Km, Kcat, and Kcat/Km of CmNAGase for pNP-GlcNAc were 16,666.67 μmol min-1 mg-1, 0.50 μmol mL-1, 25,555.56 s-1, and 51,111.12 mL μmol-1 s-1, respectively. Analysis of the hydrolysis products of N-acetyl COSs and colloidal chitin revealed that CmNAGase is a typical exo-acting NAGase. Particularly, CmNAGase can synthesize higher N-acetyl COSs ((GlcNAc)3−(GlcNAc)7) from (GlcNAc)2−(GlcNAc)6, respectively, showed that it possesses transglycosylation activity. In addition, CmNAGase also has reverse hydrolysis activity toward GlcNAc, synthesizing various linked GlcNAc dimers. Conclusions: The observations recorded in this study that CmNAGase is a novel NAGase with exo-acting, transglycosylation, and reverse hydrolysis activities, suggests a possible application in the production of GlcNAc or higher N-acetyl COSs.

scholarly journals Synthesis of Hydrophilic Poly(butylene succinate-butylene dilinoleate) (PBS-DLS) Copolymers Containing Poly(ethylene glycol) (PEG) of Variable Molecular Weights

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3177
Author(s):  
Moein Zarei ◽  
Miroslawa El Fray
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Ethylene Glycol ◽  
Polymeric Materials ◽  
Glycol Succinate ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Butylene Succinate ◽  
Molecular Weights

Polymeric materials have numerous applications from the industrial to medical fields because of their vast controllable properties. In this study, we aimed to synthesize series of poly(butylene succinate-dilinoleic succinate-ethylene glycol succinate) (PBS-DLS-PEG) copolymers, by two-step polycondensation using a heterogeneous catalyst and a two-step process. PEG of different molecular weights, namely, 1000 g/mol and 6000 g/mol, was used in order to study its effect on the surface and thermal properties. The amount of the PBS hard segment in all copolymers was fixed at 70 wt%, while different ratios between the soft segments (DLS and PEG) were applied. The chemical structure of PBS-DLS-PEG was evaluated using Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Gel permeation chromatography was used to determine the molecular weight and dispersity index. The results of structural analysis indicate the incorporation of PEG in the macrochain. The physical and thermal properties of the newly synthesized copolymers were also evaluated using water contact angle measurements, differential scanning calorimetry and dynamic thermomechanical analysis. It was found that increasing the amount of PEG of a higher molecular weight increased the surface wettability of the new materials while maintaining their thermal properties. Importantly, the two-step melt polycondensation allowed a direct fabrication of a polymeric filament with a well-controlled diameter directly from the reactor. The obtained results clearly show that the use of two-step polycondensation in the melt allows obtaining novel PBS-DLS-PEG copolymers and creates new opportunities for the controlled processing of these hydrophilic and thermally stable copolymers for 3D printing technology, which is increasingly used in medical techniques.

scholarly journals Tuning the Properties of High Molecular Weight Chitosans to Develop Full Water Solubility Within a Wide pH Range

2020 ◽  
Author(s):  
Anderson Fiamingo ◽  
Sergio Paulo Campana Filho ◽  
Osvaldo Novais Oliveira Junior
Keyword(s):  
Molecular Weight ◽  
Biomedical Applications ◽  
Random Distribution ◽  
Water Solubility ◽  
Aqueous Media ◽  
Degree Of Polymerization ◽  
Molecular Weights ◽  
H Nmr ◽  
Wide Ph Range ◽  
Ph Range

<p>The preparation of chitosans soluble in physiological conditions has been sought for years, but so far solubility in non-acidic aqueous media has only been achieved at the expense of lowering chitosan molecular weight. In this work, we applied the multistep ultrasound-assisted deacetylation process (USAD process) to β-chitin and obtained extensively deacetylated chitosans with high molecular weights (Mw ≥ 1,000,000 g mol<sup>-1</sup>). The homogeneous <i>N</i>-acetylation of a chitosan sample resulting from three consecutive USAD procedures allowed us to produce chitosans with a high weight average degree of polymerization (DPw ≈ 6,000) and tunable degrees of acetylation (DA from 5 to 80%). <i>N</i>-acetylation was carried out under mild conditions to minimize depolymerization, while preserving a predominantly random distribution of 2-amino-2-deoxy-D-glucopyanose (<i>GlcN</i>) and 2-acetamido-2-deoxy-D-glucopyanose (<i>GlcNAc</i>) units. This close to random distribution, inferred with deconvolution of nuclear magnetic resonance (<sup>1</sup>H NMR) spectra, is considered as responsible for the solubility within a wide pH range. Two of the highly <i>N</i>-acetylated chitosans (DA ≈ 60 % and ≈ 70 %) exhibited full water solubility even at neutral pH, which can expand the biomedical applications of chitosans. </p>

scholarly journals Dispersity in polymer science (IUPAC Recommendations 2009)

2009 ◽  
Vol 81 (2) ◽  
pp. 351-353 ◽  
Author(s):  
Robert F. T. Stepto
Keyword(s):  
Molecular Weight ◽  
Molecular Mass ◽  
Molar Mass ◽  
Polymeric Materials ◽  
Degree Of Polymerization ◽  
Polydispersity Index ◽  
Relative Molecular Mass ◽  
Polymer Science

This recommendation defines just three terms, viz., (1) molar-mass dispersity, relative-molecular-mass dispersity, or molecular-weight dispersity; (2) degree- of-polymerization dispersity; and (3) dispersity. "Dispersity" is a new word, coined to replace the misleading, but widely used term "polydispersity index" for Mw/Mn and Xw/Xn. The document, although brief, also has a broader significance in that it seeks to put the terminology describing dispersions of distributions of properties of polymeric (and non-polymeric) materials on an unambiguous and justifiable footing.

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