Hundschell CS, Jakob F, Wagemans AM Molecular weight dependent structure of the exopolysaccharide levan International Journal of Biological Macromolecules161 (2020)
398-405
NCBI PubMed ID:32512087 Publication DOI:10.1016/j.ijbiomac.2020.06.019 Journal NLM ID:7909578 Publisher: Butterworth-Heinemann Correspondence: christoph.hundschelltu-berlin.de Institutions: Technical University Berlin, Faculty III Process Sciences, Institute of Food Technology and Food Chemistry, Department of Food Technology and Food Material Science, Straße des 17. Juni 135, 10623 Berlin, Germany, Technical University of Munich, Chair of Technical Microbiology, Gregor-Mendel-Straße 4, 85354 Freising, Germany
Levan is a bacterial homopolysaccharide, which consists of β-2→6 linked β-(D)-fructose monomers. Because of its structural properties and its health promoting effects, levan is a promising functional ingredient for food, cosmetic and pharmaceutical products. The properties of levan have been reported to be linked to its molecular weight. For a better understanding of how the molecular weight determines its polymer conformation in aqueous solution, levan produced by the food grade acetic acid bacterium Gluconobacter albidus TMW 2.1191 was analysed over a broad molecular weight range using dynamic and static light scattering and viscometry. Low molecular weight levan exhibit a compact random coil structure. As the molecular weight increases, the structure transforms into a compact non-drained sphere. The density of the sphere continues to increase with increasing molecular weight. This resulted in a negative exponent in the Mark-Houwink-Sakurada Plot. For the first time, an increase in molecular density with increasing molecular weight, as determined by a negative Mark-Houwink-Sakurada exponent, can be shown for biopolymers. Our results reveal the unique properties of high-molecular weight levan and confirm the need of further systematic studies on the structure-function relationship of levan for its targeted use in food, cosmetic and pharmaceutical applications.
Wang Y, He P, He L, Huang Q, Cheng J, Li W, Liu Y, Wei C Structural elucidation, antioxidant and immunomodulatory activities of a novel heteropolysaccharide from cultured Paecilomyces cicadae (Miquel.) Samson Carbohydrate Polymers216 (2019)
270-281
/Variants 0/-+
|
-4)-{{{-a-D-Glcp-(1-4)-}}}/n=10/-a-D-Glcp6Me-(1-6)-b-D-Galf-(1-
/Variants 0/ is:
a-D-Glcp-(1-6)-b-D-Glcp-(1-5)-
OR (exclusively)
a-D-Glcp-(1-2)-b-D-Galp-(1-5)-
OR (exclusively)
a-D-Glcp-(1-4)-a-D-Manp-(1-5)-
Taxonomic group: fungi / Ascomycota (Phylum: Ascomycota) Organ / tissue:mycelium
The structure was elucidated in this paper NCBI PubMed ID:31047067 Publication DOI:10.1016/j.carbpol.2019.03.104 Journal NLM ID:8307156 Publisher: Elsevier Correspondence: He L <kite006126.com> Institutions: Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China, Key Laboratory of State Forest Food Resources Utilization and Quality Control, Zhejiang Provincial Key Laboratory of Forest Food, Zhejiang Academy of Forestry, Hangzhou, China, Department of Processing, Marine Fisheries Research Institute of Zhejiang, Zhoushan, China, Department of Food Science, Rutgers University, New Brunswick, NJ, USA
The fine structure and chain conformation of a heteropolysaccharide (PCIPS3) from mycelium of Paecilomyces cicadae were investigated via the analysis of HPLC, IR, methylation, NMR spectroscopy and multiangle light scattering. It was determined to be a 22300 g/mol heteropolysaccharide primarily composed of glucose, galactose and mannose in a molar ratio of 23.8:2.1:1.0. The PCIPS3 backbone consisted of 1,4-linked α-D-Glcp and 1,4-linked 6-O-Me-α-D-Glcp residues, which were occasionally interrupted by branched β-Galf residues through 1,6-linkage. Moreover, the α (0.60) from Mark-Houwink-Sakurada (MHS) equation suggested that PCIPS3 adopted a flexible chain conformation in 0.1 mol/L NaNO3 at 25 °C. The worm-like chains model parameters for PCIPS3 were estimated as following: ML = 437 nm-1, q = 0.46 nm and 0.79 nm, which were further evidenced by AFM. Furthermore, PCIPS3 showed excellent scavenging capacities of 2,2-diphenyl-1-picrylhydrazyl radical, superoxide radical, hydroxyl radical, ORAC radical and moderate immunomodulatory activity.
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