Non-classical secondary cell wall polysaccharides constitute a major cell wall structure in the Bacillus cereus group of bacteria. The structure of the secondary cell wall polysaccharide from Bacillus cereus ATCC 10987, a strain that is closely related to B. anthracis, was determined. This polysaccharide was released from the cell wall with aqueous hydrogen fluoride (HF) and purified by gel filtration chromatography. The purified polysaccharide, HF-PS, was characterized by glycosyl composition and linkage analyses, mass spectrometry, and 1- and 2-D NMR analysis. The results showed that the B. cereus ATCC 10987 HF-PS has a repeating oligosaccharide consisting of a 6)--GalNAc-(14)--ManNAc-(14)--GlcNAc-(1 trisaccharide that is substituted with -Gal at O3 of the -GalNAc residue, and non-stoichiometrically acetylated at O3 of the ManNAc residue. Comparison of this structure with that of the B. anthracis HF-PS and with structural data obtained for the HF-PS from B. cereus type strain ATCC 14579 revealed that each HF-PS had the same general structural theme consisting of three HexNAc and one Hex residues. A common structural feature in the HF-PSs from B. cereus ATCC 10987 and B. anthracis was the presence of a repeating unit consisting of a HexNAc3 trisaccharide backbone in which two of the three HexNAc residues are GlcNAc and ManNAc, and the third can be either GlcNAc or GalNAc. The implications of these results with regard to the possible functions of the HF-PSs are discussed

structure, repeating unit, Bacillus, cell wall polysaccharide, Bacillus cereus

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
4,4,2	Ac
4,4,3	bDGalp	104.8	71.0	72.8	69.0	72.8	61.3
4,4	aDGalpN	97.6	48.2	?	68.7	70.0	69.5
4,2	Ac
4,3	%Ac
4	bDManpN	98.6	50.8	75.8	75.5	75.6	61.4
2	Ac
	bDGlcpN	101.9	55.1	70.9	79.3	74.9	60.5


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
4,4,2	Ac	-	2.0
4,4,3	bDGalp	4.45	3.52	3.62	3.91	3.63	3.92-3.92
4,4	aDGalpN	5.23	4.32	4.23	4.23	3.93	3.78-4.06
4,2	Ac	-	2.0
4,3	%Ac
4	bDManpN	5.04	4.66	5.15	3.94	3.65	3.83-3.92
2	Ac	-	2.0
	bDGlcpN	4.57	3.78	3.73	3.53	3.71	3.74-3.88


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
4,4,2	Ac	NMR TSV error 2: unequal length of 13C and 1H datasets
4,4,3	bDGalp	104.8/4.45	71.0/3.52	72.8/3.62	69.0/3.91	72.8/3.63	61.3/3.92-3.92
4,4	aDGalpN	97.6/5.23	48.2/4.32	?/4.23	68.7/4.23	70.0/3.93	69.5/3.78-4.06
4,2	Ac	NMR TSV error 2: unequal length of 13C and 1H datasets
4,3	%Ac
4	bDManpN	98.6/5.04	50.8/4.66	75.8/5.15	75.5/3.94	75.6/3.65	61.4/3.83-3.92
2	Ac	NMR TSV error 2: unequal length of 13C and 1H datasets
	bDGlcpN	101.9/4.57	55.1/3.78	70.9/3.73	79.3/3.53	74.9/3.71	60.5/3.74-3.88

The spectrum also has 1 signal at unknown position (not plotted).

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

*OC[C@H]1O[C@H](O[C@@H]2[C@@H](CO)O[C@@H](O[C@@H]3[C@@H](CO)O[C@@H](*)[C@H](NC(C)=O)[C@H]3O)[C@@H](NC(C)=O)[C@H]2OC(C)=O)[C@H](NC(C)=O)[C@@H](O[C@@H]2O[C@H](CO)[C@H](O)[C@H](O)[C@H]2O)[C@H]1O

813.76 g/mol (C₃₂H₅₁R₂N₃O₂₁, R = next and previous repeats, not counted in mol weight)