Comparative analysis of different xanthan samples by atomic force microscopy

Teckentrup, Julia; Al-Hammood, Orooba; Steffens, Tim; Bednarz, Hanna; Walhorn, Volker; Niehaus, Karsten; Anselmetti, Dario

doi:10.1016/j.jbiotec.2016.11.032

Cited by 24 publications

(13 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Unlike the other samples, terminal mannosyl residue-free xanthan (TMFX) exposed more random-coil structures, with the lowest mean height being 0.48 Ϯ 0.07 nm (Fig. 7e and f), suggesting more single-stranded polymers, which is consistent with a previous report (20). The mean height of xanthan samples after incubation with MiXen was then calculated.…”

Section: Resultssupporting

confidence: 87%

“…It is known that the final degree of enzymolysis could be influenced by the secondary xanthan structure (8), and that changes in xanthan structure depend on different factors, including temperature, pH, ionic strength, and modifications of the xanthan side chain (20,34,35). In this study, xanthan degradation was conducted under set temperature, pH, and ionic strength; thus, the effect of xanthan side chain modification on MiXen activity via changes in xanthan structure was further investigated.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Novel Endotype Xanthanase from Xanthan-Degrading Microbacterium sp. Strain XT11

Yang

Sun

et al. 2019

Appl Environ Microbiol

View full text Add to dashboard Cite

Under general aqueous conditions, xanthan appears in an ordered conformation, which makes its backbone largely resistant to degradation by known cellulases. Therefore, the xanthan degradation mechanism is still unclear because of the lack of an efficient hydrolase. Here, we report the catalytic properties of MiXen, a xanthan-degrading enzyme identified from the genus Microbacterium. MiXen is a 952-amino-acid protein that is unique to strain XT11. Both the sequence and structural features suggested that MiXen belongs to a new branch of the GH9 family and has a multimodular structure in which a catalytic (α/α)6 barrel is flanked by an N-terminal Ig-like domain and by a C-terminal domain that has very few homologues in sequence databases and functions as a carbohydrate-binding module (CBM). Based on circular dichroism, shear-dependent viscosity, and reducing sugar and gel permeation chromatography analysis, we demonstrated that recombinant MiXen efficiently and randomly cleaved glucosidic bonds within the highly ordered xanthan substrate. A MiXen mutant free of the C-terminal CBM domain partially lost its xanthan-hydrolyzing ability because of decreased affinity toward xanthan, indicating the CBM domain assisted MiXen in hydrolyzing highly ordered xanthan via recognizing and binding to the substrate. Furthermore, side chain substituents and the terminal mannosyl residue significantly influenced the activity of MiXen via the formation of barriers to enzymolysis. Overall, the results of this study provide insight into the hydrolysis mechanism and enzymatic properties of a novel endotype xanthanase that will benefit future applications. IMPORTANCE This work characterized a novel endotype xanthanase, MiXen, and elucidated that the C-terminal carbohydrate-binding module of MiXen could drastically enhance the hydrolysis activity of the enzyme toward highly ordered xanthan. Both the sequence and structural analysis demonstrated that the catalytic domain and carbohydrate-binding module of MiXen belong to the novel branch of the GH9 family and CBMs, respectively. This xanthan cleaver can help further reveal the enzymolysis mechanism of xanthan and provide an efficient tool for the production of molecular modified xanthan with new physicochemical and physiological functions.

show abstract

Section: Resultssupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Novel Endotype Xanthanase from Xanthan-Degrading Microbacterium sp. Strain XT11

Yang

Sun

et al. 2019

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…Similar studies have been conducted to determine the size of a single cellulose nanocrystal; AFM has provided an efficient way to evaluate the length, width, and aspect ratios of these individual crystals ( Figure 13) [81]. The difference in the molecular structure of the biopolymers has also been determined by the AFM technique; the molecular structure of xanthan biopolymer produced by several different strains of Xanthomonas campestris was studied by AFM [77]. The AFM images depicted in Figure 14 revealed different structural features for different strains.…”

Section: (A) Atomic Force Microscopymentioning

confidence: 96%

“…Particle dispersion Cellulose nanofiber [74] Particle Size Kondagogu gum biopolymer assisted Pt nanoparticles [24] Core shell structure Chitosan/PEO [75] TEM + selected area electron diffraction Crystallographic analysis Biopolymer assisted nanoparticles [21,24] Atomic force microscopy Molecular structure and conformation Xanthan gum [76][77][78] Nanomaterial topography Nanocellulose [79,80] Particle size and shape Nanocellulose [81] Chemical force microscopy Chemical interactions Chitosan [82] Magnetic force microscopy Magnetic properties Chitosan based magnetic nanohydrogels [83] Scanning tunneling microscopy Molecular structure Particle Size Surface modification…”

Section: Technique Application Biopolymer Referencesmentioning

confidence: 99%

“…The difference in the molecular structure of the biopolymers has also been determined by the AFM technique; the molecular structure of xanthan biopolymer produced by several different strains of Xanthomonas campestris was studied by AFM [77]. Similar studies have been conducted to determine the size of a single cellulose nanocrystal; AFM has provided an efficient way to evaluate the length, width, and aspect ratios of these individual crystals ( Figure 13) [81].…”

Section: (A) Atomic Force Microscopymentioning

confidence: 99%

See 1 more Smart Citation

Microscopic Techniques for the Analysis of Micro and Nanostructures of Biopolymers and Their Derivatives

et al. 2020

View full text Add to dashboard Cite

Natural biopolymers, a class of materials extracted from renewable sources, is garnering interest due to growing concerns over environmental safety; biopolymers have the advantage of biocompatibility and biodegradability, an imperative requirement. The synthesis of nanoparticles and nanofibers from biopolymers provides a green platform relative to the conventional methods that use hazardous chemicals. However, it is challenging to characterize these nanoparticles and fibers due to the variation in size, shape, and morphology. In order to evaluate these properties, microscopic techniques such as optical microscopy, atomic force microscopy (AFM), and transmission electron microscopy (TEM) are essential. With the advent of new biopolymer systems, it is necessary to obtain insights into the fundamental structures of these systems to determine their structural, physical, and morphological properties, which play a vital role in defining their performance and applications. Microscopic techniques perform a decisive role in revealing intricate details, which assists in the appraisal of microstructure, surface morphology, chemical composition, and interfacial properties. This review highlights the significance of various microscopic techniques incorporating the literature details that help characterize biopolymers and their derivatives.

show abstract

Xanthan gum enhances peripheral blood CIK cells cytotoxicity in serum‐free medium

Gong

Zhu

Tan

et al. 2022

Biotechnology Progress

View full text Add to dashboard Cite

As a water‐soluble macromolecule polysaccharide, xanthan gum (XG) has several biological activities, such as antitumor, antiviral, and immunomodulatory function. However, the effect of XG on the proliferation and cytotoxicity of cytokines induced killer (CIK) cells is rarely studied. In this study, the effect of XG on CIK cells derived from peripheral blood was investigated by analyzing the expansion fold of total cells, phenotype, cytotoxicity, degranulation, and apoptosis in serum‐free medium. The results showed that the expansion fold of total cells with 100 μg/ml XG which molecule weight is 2.95 × 106 Da reached 4534.0 folds, significantly higher than that without XG (1299.0 folds, p < 0.05). The percentage of main effector cells‐CD3+CD56+ cells increased to 25.5% and the cytotoxic activity of CIK cells increased to 45.3%. The cell proportions of expression granzyme B and perforin that related to cytotoxicity in CIK cells reached 53.6% and 48.3%, respectively, significantly higher than 27.5% and 37.5% in the group without XG (p < 0.05). Collectively, XG could stimulate the ex vivo expansion of CIK cells and enhance the cytotoxicity of expanded CIK cells. The above results provide technical support for optimizing the expansion process of CIK cells ex vivo.

show abstract

Comparative analysis of different xanthan samples by atomic force microscopy

Cited by 24 publications

References 23 publications

Novel Endotype Xanthanase from Xanthan-Degrading Microbacterium sp. Strain XT11

Novel Endotype Xanthanase from Xanthan-Degrading Microbacterium sp. Strain XT11

Microscopic Techniques for the Analysis of Micro and Nanostructures of Biopolymers and Their Derivatives

Xanthan gum enhances peripheral blood CIK cells cytotoxicity in serum‐free medium

Contact Info

Product

Resources

About