The exopolysaccharide (EPS) from Lactobacillus delbrueckii subsp. bulgaricus EU23 was perdeuteriomethylated and the perdeuteriomethylated EPS (pdm-EPS) purified by elution from a C(18) Sep-Pak cartridge. Both 1D and 2D NMR spectra were recorded for the pdm-EPS and these were interpreted to provide assignments for the individual 1H and 13C resonances of the sugar residues of the repeating unit. [-2)aLRhap(1-4)aDGlcp(1-3)bLRha?(1-4)bDGlcp(1-4)[aLRha?(1-3)]aDGlcp(1-] Using a combination of the results from monomer analysis and linkage analysis of the native EPS and the ROESY and HMBC NMR spectra of the pdm-EPS the following structure has been determined for the repeating unit:A process for characterising polysaccharides having low solubility in aqueous solution is reported

structure, NMR spectroscopy, exopolysaccharide, 2D NMR, Lactobacillus delbrueckii

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
4,4,3,4,3	Me
4,4,3,4,4	Me
4,4,3,4	aLRhap	98.3	74.5	80.8	82.4	68.5	18.3
4,4,3,2	Me
4,4,3,3	Me
4,4,3,6	Me
4,4,3	aDGlcp	93.0	82.2	81.8	75.8	70.7	70.9
4,4,2	Me
4,4,4	Me
4,4	bLRhap	102.2	77.4	77.7	81.8	71.9	18.5
4,2	Me
4,3	Me
4,6	Me
4	bDGlcp	101.9	84.8	86.5	76.8	75.3	72.4
2	Me
3,2	Me
3,3	Me
3,4	Me
3	aLRhap	97.8	78.2	80.8	83.0	67.1	18.7
6	Me
	aDGlcp	95.6	83.2	74.7	73.5	71.5	72.0


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
4,4,3,4,3	Me
4,4,3,4,4	Me
4,4,3,4	aLRhap	4.83	3.91	3.38	3.04	3.76	1.18
4,4,3,2	Me
4,4,3,3	Me
4,4,3,6	Me
4,4,3	aDGlcp	5.14	3.20	3.41	3.55	3.83	3.52-3.69
4,4,2	Me
4,4,4	Me
4,4	bLRhap	4.60	3.69	3.54	3.03	3.15	1.24
4,2	Me
4,3	Me
4,6	Me
4	bDGlcp	4.32	2.84	3.16	3.26	3.28	3.48-3.88
2	Me
3,2	Me
3,3	Me
3,4	Me
3	aLRhap	5.07	3.51	3.59	2.96	4.24	1.11
6	Me
	aDGlcp	5.02	3.20	3.78	3.68	4.00	3.43-3.60


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
4,4,3,4,3	Me
4,4,3,4,4	Me
4,4,3,4	aLRhap	98.3/4.83	74.5/3.91	80.8/3.38	82.4/3.04	68.5/3.76	18.3/1.18
4,4,3,2	Me
4,4,3,3	Me
4,4,3,6	Me
4,4,3	aDGlcp	93.0/5.14	82.2/3.20	81.8/3.41	75.8/3.55	70.7/3.83	70.9/3.52-3.69
4,4,2	Me
4,4,4	Me
4,4	bLRhap	102.2/4.60	77.4/3.69	77.7/3.54	81.8/3.03	71.9/3.15	18.5/1.24
4,2	Me
4,3	Me
4,6	Me
4	bDGlcp	101.9/4.32	84.8/2.84	86.5/3.16	76.8/3.26	75.3/3.28	72.4/3.48-3.88
2	Me
3,2	Me
3,3	Me
3,4	Me
3	aLRhap	97.8/5.07	78.2/3.51	80.8/3.59	83.0/2.96	67.1/4.24	18.7/1.11
6	Me
	aDGlcp	95.6/5.02	83.2/3.20	74.7/3.78	73.5/3.68	71.5/4.00	72.0/3.43-3.60

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]O[C@H]1[C@H](O[C@H]2[C@H](OC)[C@@H](OC)[C@@H](O[C@@H]3[C@@H](OC)[C@H](C)O[C@H](O[C@H]4[C@H](OC)[C@@H](OC)[C@H](O[C@@H]5[C@@H](COC)O[C@H]([*])[C@H](OC)[C@H]5O[C@@H]5O[C@@H](C)[C@H](OC)[C@@H](OC)[C@H]5OC)O[C@@H]4COC)[C@@H]3OC)O[C@@H]2COC)O[C@@H](C)[C@H](OC)[C@H]1OC

1135.254 g/mol (C₅₁H₉₀R₂O₂₇, R = next and previous repeats, not counted in mol weight)

The exopolysaccharide (EPS) from Lactobacillus delbrueckii subsp. bulgaricus EU23 was perdeuteriomethylated and the perdeuteriomethylated EPS (pdm-EPS) purified by elution from a C(18) Sep-Pak cartridge. Both 1D and 2D NMR spectra were recorded for the pdm-EPS and these were interpreted to provide assignments for the individual 1H and 13C resonances of the sugar residues of the repeating unit. [-2)aLRhap(1-4)aDGlcp(1-3)bLRha?(1-4)bDGlcp(1-4)[aLRha?(1-3)]aDGlcp(1-] Using a combination of the results from monomer analysis and linkage analysis of the native EPS and the ROESY and HMBC NMR spectra of the pdm-EPS the following structure has been determined for the repeating unit:A process for characterising polysaccharides having low solubility in aqueous solution is reported

structure, NMR spectroscopy, exopolysaccharide, 2D NMR, Lactobacillus delbrueckii

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]O[C@H]1[C@H](O[C@@H]2[C@@H](CO)O[C@H](O[C@@H]3[C@@H](O)[C@H](C)O[C@H](O[C@@H]4[C@@H](CO)O[C@@H](O[C@@H]5[C@@H](CO)O[C@H]([*])[C@H](O)[C@H]5O[C@@H]5O[C@@H](C)[C@H](O)[C@@H](O)[C@H]5O)[C@H](O)[C@H]4O)[C@@H]3O)[C@H](O)[C@H]2O)O[C@@H](C)[C@H](O)[C@H]1O

924.849 g/mol (C₃₆H₆₀R₂O₂₇, R = next and previous repeats, not counted in mol weight)