Alteromonas macleodii ATCC 27126T is a Gram-negative marine bacterium isolated from a sea water sample collected from around the Hawaiian Islands. The structure of the lipooligosaccharide derived from its outer membrane has been fully determined using either alkaline or acid hydrolysis. Alkaline treatment, aimed at recovering the complete carbohydrate backbone, was carried out by mild hydrazinolysis (de-O-acylation) followed by de-N-acylation using hot KOH and furnished a single core glycoform. Mild acid hydrolysis was employed to obtain the lipid A moiety which was selectively de-O-acylated and analysed to determine its primary structure. The structural elucidation of both fractions was carried out by chemical analyses, 2D NMR spectroscopy and MALDI-TOF mass spectrometry and revealed a novel lipooligosaccharide with an unusual structure.

Lipopolysaccharide, Marine bacteria, Alteromonas macleodii

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6	C7	C8
0,6,6,5,7	bXKdop	?	?	34.5	67.7	65.6	73.5	69.2	64.2
0,6,6,5	aXLDmanHepp	100.4	70.2	70.7	66.9	73.3	70.2	64.7
0,6,6,4	P
0,6,6	aXKdop	?	?	34.2	70.1	72.4	71.9	69.4	63.6
0,6,4	P
0,6	bDGlcpN	99.2	55.6	74.4	71.8	74.0	62.4
0	aDGlcpN	91.4	54.2	69.7	69.9	72.7	69.3
	P


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6	H7	H8
0,6,6,5,7	bXKdop	-	-	1.84-2.44	3.763	3.949	3.596	3.934	3.766-3.884
0,6,6,5	aXLDmanHepp	5.147	4.086	3.888	3.736	4.222	4.218	3.592-3.974
0,6,6,4	P
0,6,6	aXKdop	-	-	2.02-2.22	3.894	4.308	3.814	3.812	3.693-3.932
0,6,4	P
0,6	bDGlcpN	4.914	3.121	3.889	3.884	3.772	3.513-3.729
0	aDGlcpN	5.704	3.432	3.908	3.488	4.143	3.874-4.289
	P


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6	C7/H7	C8/H8
0,6,6,5,7	bXKdop			34.5/1.84-2.44	67.7/3.763	65.6/3.949	73.5/3.596	69.2/3.934	64.2/3.766-3.884
0,6,6,5	aXLDmanHepp	100.4/5.147	70.2/4.086	70.7/3.888	66.9/3.736	73.3/4.222	70.2/4.218	64.7/3.592-3.974
0,6,6,4	P
0,6,6	aXKdop			34.2/2.02-2.22	70.1/3.894	72.4/4.308	71.9/3.814	69.4/3.812	63.6/3.693-3.932
0,6,4	P
0,6	bDGlcpN	99.2/4.914	55.6/3.121	74.4/3.889	71.8/3.884	74.0/3.772	62.4/3.513-3.729
0	aDGlcpN	91.4/5.704	54.2/3.432	69.7/3.908	69.9/3.488	72.7/4.143	69.3/3.874-4.289
	P

The spectrum also has 4 signals at unknown positions (not plotted).

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

N[C@H]1[C@@H](OP(=O)(O)O)O[C@H](CO[C@@H]2O[C@H](CO[C@]3(C(=O)O)C[C@@H](OP(=O)(O)O)[C@@H](O[C@H]4O[C@H]([C@@H](O)CO[C@@]5(C(=O)O)C[C@@H](O)[C@@H](O)[C@@H]([C@H](O)CO)O5)[C@@H](O)[C@H](O)[C@@H]4O)[C@@H]([C@H](O)CO)O3)[C@@H](OP(=O)(O)O)[C@H](O)[C@H]2N)[C@@H](O)[C@@H]1O

1212.787 g/mol (C₃₅H₆₃N₂O₃₈P₃)

Alteromonas macleodii ATCC 27126T is a Gram-negative marine bacterium isolated from a sea water sample collected from around the Hawaiian Islands. The structure of the lipooligosaccharide derived from its outer membrane has been fully determined using either alkaline or acid hydrolysis. Alkaline treatment, aimed at recovering the complete carbohydrate backbone, was carried out by mild hydrazinolysis (de-O-acylation) followed by de-N-acylation using hot KOH and furnished a single core glycoform. Mild acid hydrolysis was employed to obtain the lipid A moiety which was selectively de-O-acylated and analysed to determine its primary structure. The structural elucidation of both fractions was carried out by chemical analyses, 2D NMR spectroscopy and MALDI-TOF mass spectrometry and revealed a novel lipooligosaccharide with an unusual structure.

Lipopolysaccharide, Marine bacteria, Alteromonas macleodii

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

CCCCCCCCCCCC(=O)OC(CCCCCCCCC)CC(=O)N[C@H]1[C@H](OC[C@H]2O[C@H](OP(=O)(O)O)[C@H](NC(=O)CC(O)CCCCCCCCC)[C@@H](OC(=O)CC(O)CCCCCCCCC)[C@@H]2O)O[C@H](CO[C@]2(C(=O)O)C[C@@H](OP(=O)(O)OP(=O)(O)OCCN)[C@@H](O[C@H]3O[C@H]([C@@H](O)CO[C@@]4(C(=O)O)C[C@@H](O)[C@@H](O)[C@@H]([C@H](O)CO)O4)[C@@H](O)[C@H](O)[C@@H]3O)[C@@H]([C@H](O)CO)O2)[C@@H](OP(=O)(O)O)[C@@H]1OC(=O)CC(O)CCCCCCCCC

2311.366 g/mol (C₉₇H₁₇₉N₃O₅₀P₄)