1.0 2011-09-21 01:56:20 UTC 2015-07-21 06:59:44 UTC FDB029470 LPS-o-antigen Lipopolysaccharides (LPS), also known as lipoglycans, are large molecules consisting of a lipid and a polysaccharide joined by a covalent bond; they are found in the outer membrane of Gram-negative bacteria, act as endotoxins and elicit strong immune responses in animals. LPS is the major component of the outer membrane of Gram-negative bacteria, contributing greatly to the structural integrity of the bacteria, and protecting the membrane from certain kinds of chemical attack. LPS also increases the negative charge of the cell membrane and helps stabilize the overall membrane structure. It is of crucial importance to gram negative bacteria, whose death results if it is mutated or removed. LPS is an endotoxin, and induces a strong response from normal animal immune systems. LPS acts as the prototypical endotoxin because it binds the CD14/TLR4/MD2 receptor complex, which promotes the secretion of pro-inflammatory cytokines in many cell types, but especially in macrophages. In Immunology, the term "LPS challenge" refers to the process of exposing a subject to an LPS which may act as a toxin. LPS is also an exogenous pyrogen (external fever-inducing substance). Being of crucial importance to gram negative bacteria, these molecules make candidate targets for new antimicrobial agents. LPS comprises three parts: 1. O antigen (or O polysaccharide). 2. Core polysaccharide. 3. Lipid A The making of LPS can be modified in order to present a specific sugar structure. Those can be recognised by either other LPS (which enables to inhibit LPS toxins) or glycosyltransferases which use those sugar structure to add more specific sugars. It has recently been shown that a specific enzyme in the intestine (alkaline phosphatase) can detoxify LPS by removing the two phosphate groups found on LPS carbohydrates [6]. This may function as an adaptive mechanism to help the host manage potentially toxic effects of gram-negative bacteria normally found in the small intestine. (from wiki) This card shows the example of LPS in E. coli with one o-antigen unit. [HMDB] endotoxin endotoxin Lipopolysaccharide endotoxin LPS Lipopolysaccharide Lipopolysaccharide with O-antigen Lipopolysaccharide-o-antigen LPS C93H175N2O21P 1688.39 1687.242497661 N-[2-({5-[(1,3-dihydroxytetradecylidene)amino]-6-hydroxy-4-[(3-hydroxytetradecanoyl)oxy]oxan-2-yl}oxy)-6-(hydroxymethyl)-5-(phosphonooxy)-4-{[3-(tetradecanoyloxy)tetradecanoyl]oxy}oxan-3-yl]-3-(dodecanoyloxy)tetradecanimidic acid N-[2-({5-[(1,3-dihydroxytetradecylidene)amino]-6-hydroxy-4-[(3-hydroxytetradecanoyl)oxy]oxan-2-yl}oxy)-6-(hydroxymethyl)-5-(phosphonooxy)-4-{[3-(tetradecanoyloxy)tetradecanoyl]oxy}oxan-3-yl]-3-(dodecanoyloxy)tetradecanimidic acid CCCCCCCCCCCCCC(=O)OC(CCCCCCCCCCC)CC(=O)OC1C(OP(O)(O)=O)C(CO)OC(OC2CC(OC(=O)CC(O)CCCCCCCCCCC)C(N=C(O)CC(O)CCCCCCCCCCC)C(O)O2)C1N=C(O)CC(CCCCCCCCCCC)OC(=O)CCCCCCCCCCC InChI=1S/C93H175N2O21P/c1-7-13-19-25-31-37-38-44-50-56-62-68-84(102)110-78(66-60-54-48-42-35-29-23-17-11-5)72-86(104)113-91-89(95-82(100)71-77(65-59-53-47-41-34-28-22-16-10-4)109-83(101)67-61-55-49-43-36-30-24-18-12-6)93(112-80(74-96)90(91)116-117(106,107)108)115-87-73-79(111-85(103)70-76(98)64-58-52-46-40-33-27-21-15-9-3)88(92(105)114-87)94-81(99)69-75(97)63-57-51-45-39-32-26-20-14-8-2/h75-80,87-93,96-98,105H,7-74H2,1-6H3,(H,94,99)(H,95,100)(H2,106,107,108) HSNYRLYFFRIIEC-UHFFFAOYSA-N belongs to the class of organic compounds known as acylaminosugars. These are organic compounds containing a sugar linked to a chain through N-acyl group. Acylaminosugars Organic compounds Organic oxygen compounds Organooxygen compounds Carbohydrates and carbohydrate conjugates Aliphatic heteromonocyclic compounds Acetals Beta hydroxy acids and derivatives Carbonyl compounds Carboxylic acid esters Fatty acid esters Hemiacetals Hydrocarbon derivatives Monosaccharides N-acyl amines N-acyl-alpha-hexosamines O-glycosyl compounds Organic oxides Organic zwitterions Organonitrogen compounds Organopnictogen compounds Oxacyclic compounds Oxanes Primary alcohols Saccharolipids Secondary alcohols Secondary carboxylic acid amides Tetracarboxylic acids and derivatives Acetal Acylaminosugar Alcohol Aliphatic heteromonocyclic compound Beta-hydroxy acid Carbonyl group Carboxamide group Carboxylic acid derivative Carboxylic acid ester Fatty acid ester Fatty acyl Fatty amide Glycosyl compound Hemiacetal Hydrocarbon derivative Hydroxy acid Monosaccharide N-acyl-alpha-hexosamine N-acyl-amine O-glycosyl compound Organic nitrogen compound Organic oxide Organic zwitterion Organoheterocyclic compound Organonitrogen compound Organopnictogen compound Oxacycle Oxane Primary alcohol Saccharolipid Secondary alcohol Secondary carboxylic acid amide Tetracarboxylic acid or derivatives Solid logp 7.28 ALOGPS logs -6.53 ALOGPS solubility 4.94e-04 g/l ALOGPS logp 25.58 ChemAxon pka_strongest_acidic 0.52 ChemAxon pka_strongest_basic 4.72 ChemAxon iupac N-[2-({5-[(1,3-dihydroxytetradecylidene)amino]-6-hydroxy-4-[(3-hydroxytetradecanoyl)oxy]oxan-2-yl}oxy)-6-(hydroxymethyl)-5-(phosphonooxy)-4-{[3-(tetradecanoyloxy)tetradecanoyl]oxy}oxan-3-yl]-3-(dodecanoyloxy)tetradecanimidic acid ChemAxon average_mass 1688.39 ChemAxon mono_mass 1687.242497661 ChemAxon smiles CCCCCCCCCCCCCC(=O)OC(CCCCCCCCCCC)CC(=O)OC1C(OP(O)(O)=O)C(CO)OC(OC2CC(OC(=O)CC(O)CCCCCCCCCCC)C(N=C(O)CC(O)CCCCCCCCCCC)C(O)O2)C1N=C(O)CC(CCCCCCCCCCC)OC(=O)CCCCCCCCCCC ChemAxon formula C93H175N2O21P ChemAxon inchi InChI=1S/C93H175N2O21P/c1-7-13-19-25-31-37-38-44-50-56-62-68-84(102)110-78(66-60-54-48-42-35-29-23-17-11-5)72-86(104)113-91-89(95-82(100)71-77(65-59-53-47-41-34-28-22-16-10-4)109-83(101)67-61-55-49-43-36-30-24-18-12-6)93(112-80(74-96)90(91)116-117(106,107)108)115-87-73-79(111-85(103)70-76(98)64-58-52-46-40-33-27-21-15-9-3)88(92(105)114-87)94-81(99)69-75(97)63-57-51-45-39-32-26-20-14-8-2/h75-80,87-93,96-98,105H,7-74H2,1-6H3,(H,94,99)(H,95,100)(H2,106,107,108) ChemAxon inchikey HSNYRLYFFRIIEC-UHFFFAOYSA-N ChemAxon polar_surface_area 345.75 ChemAxon refractivity 460.91 ChemAxon polarizability 206.46 ChemAxon rotatable_bond_count 85 ChemAxon acceptor_count 18 ChemAxon donor_count 8 ChemAxon physiological_charge -2 ChemAxon formal_charge 0 ChemAxon HMDB13470 16412