Taxonomic group: bacteria / Firmicutes
(Phylum: Firmicutes)
The structure was elucidated in this paperNCBI PubMed ID: 32475665Publication DOI: 10.3168/jds.2019-17439Journal NLM ID: 2985126RPublisher: Champaign, IL: American Dairy Science Association
Correspondence: npshah
hku.hk
Institutions: Food and Nutritional Science, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
In this study, we purified and characterized exopolysaccharide (EPS) produced by a high-EPS-producing dairy starter bacterium, Streptococcus thermophilus ASCC 1275. Crude EPS was extracted from S. thermophilus ASCC 1275 and partially purified using dialysis. Further purification and fractionation of exopolysaccharide was conducted using HPLC on a Superose 6 column (Cytiva/Global Life Sciences Solutions, Marlborough, MA). Glycosyl composition analysis, linkage analysis along with 1-dimensional and 2-dimensional nuclear magnetic resonance spectroscopy were performed to deduce the structure of EPS. Three fractions (F) obtained from gel permeation chromatography were termed F1 (2.6%), F2 (45.8%), and F3 (51.6%) with average molecular weights of approximately 511, 40, and 5 kDa, respectively. Monosaccharide composition analysis revealed the dominance of glucose, galactose, and mannose in all 3 fractions. Major linkages observed in F3 were terminal galactopyranosyl (t-Gal), 3-linked glucopyranosyl (3-Glc), 3-linked galactofuranosyl (3-Galf), and 3,6-linked glucopyranosyl (3,6-Glc) and major linkages present in F2 were 4-Glc (48 mol%), followed by terminal mannopyranosyl (t-Man), 2- + 3-linked mannopyranosyl (2-Man+3-Man), and 2,6-linked mannopyranosyl (2,6-Man; total ~28 mol%). The 1-dimensional and 2-dimensional nuclear magnetic resonance spectroscopy revealed that F2 comprised mannans linked by (1→2) linkages and F3 consisted of linear chains of α-d-glucopyranosyl (α-d-Glcp), β-d-glucopyranosyl (β-d-Glcp), and β-d-galactofuranosyl (β-d-Galf) connected by (1→3) linkages; branching was through (1→6) linkage in F3. A possible structure of EPS in F2 and F3 was proposed.
structure, exopolysaccharide, nuclear magnetic resonance (NMR), glycosyl linkage
Structure type: homopolymer
Location inside paper: Fig.4, Fig.7, table 5, structure 3
Trivial name: pustulan, β-1,6-glucan, β-1,6-D-glucan, β(1-6)-D-glucan, β-(1,6)-glucan, lasiodiplodan, pustulan, β-(1,6)-glucan, lasiodiplodan, β-(1,6)-glucan, β-(1,6)-glucan, lasiodiplodan, pustulan, β-1,6-glucan, β-(1,6)-glucan, pustulan, β-(1→6)-glucan PCPS, water-soluble glucan (PS-I)
Compound class: EPS, O-polysaccharide, cell wall polysaccharide, glycoprotein, glucan, polysaccharide, cell wall glucoprotein
Contained glycoepitopes: IEDB_135614,IEDB_141806,IEDB_142488,IEDB_146664,IEDB_241101,IEDB_983931,SB_192
Methods: 13C NMR, 1H NMR, methylation, NMR-2D, GC-MS, composition analysis, HPLC, enzymatic digestion, SEC
Comments, role: structure 3 of EPS from fraction 3.
Related record ID(s): 5186, 5188, 5189, 32173
NCBI Taxonomy refs (TaxIDs): 1408178Reference(s) to other database(s): GTC:G26777BZ, GlycomeDB:
863, CCSD:
50854, CBank-STR:4234
Show glycosyltransferases
NMR conditions: in D2O at 298 K
[as TSV]
13C NMR data:
Linkage Residue C1 C2 C3 C4 C5 C6
bDGlcp 105.8 75.8 78.3 72.2 77.7 71.6
1H NMR data:
Linkage Residue H1 H2 H3 H4 H5 H6
bDGlcp 4.53 3.33 3.51 3.48 3.64 3.86-4.23
1H/13C HSQC data:
Linkage Residue C1/H1 C2/H2 C3/H3 C4/H4 C5/H5 C6/H6
bDGlcp 105.8/4.53 75.8/3.33 78.3/3.51 72.2/3.48 77.7/3.64 71.6/3.86-4.23
1H NMR data:
| Linkage | Residue | H1 | H2 | H3 | H4 | H5 | H6 |
|---|
| | bDGlcp | 4.53 | 3.33 | 3.51 | 3.48 | 3.64 | 3.86
4.23 |
|
13C NMR data:
| Linkage | Residue | C1 | C2 | C3 | C4 | C5 | C6 |
|---|
| | bDGlcp | 105.8 | 75.8 | 78.3 | 72.2 | 77.7 | 71.6 |
|
There is only one chemically distinct structure:
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