Rietschel E T, Wollenweber H W, Russa R, Brade H, Zähringer U
Rev Infect Dis. 1984 Jul-Aug;6(4):432-8. doi: 10.1093/clinids/6.4.432.
Lipid A represents the covalently bound lipid component of lipopolysaccharides (LPS), the endotoxins and O antigens of gram-negative bacteria. Lipid A's of endotoxically active LPS consist of a beta(1'----6)-linked D-glucosamine disaccharide that carries phosphoryl groups in positions 1 and 4'. Depending on the origin of lipid A, nonacylated, nitrogen-containing residues may be bound to these phosphoryl groups. As shown in enterobacterial lipid A's, available hydroxyl groups of the D-glucosamine disaccharide are substituted by 3-deoxy-D-mannooctulosonic acid (position 6'), (R)-3-hydroxytetradecanoic acid (position 3), and (R)-3-(tetradecanoyloxy)tetradecanoic acid (position 3'). The hydroxyl group at C-4 appears to be free. The amino groups of the disaccharide carry (R)-3-(acyloxy)acyl [and (R)-3-hydroxyacyl] residues in a specific distribution. On the basis of these data, a proposal for a general structure of lipid A is made. As a specific example of this general architecture, the chemical structure of lipid A of Salmonella minnesota LPS is presented.
脂质A是脂多糖（LPS）的共价结合脂质成分，脂多糖是革兰氏阴性菌的内毒素和O抗原。具有内毒素活性的LPS的脂质A由一个β（1'→6）连接的D-葡糖胺二糖组成，该二糖在1位和4'位带有磷酸基团。根据脂质A的来源，非酰化的含氮残基可能与这些磷酸基团结合。如在肠杆菌脂质A中所示，D-葡糖胺二糖的可用羟基被3-脱氧-D-甘露辛酮酸（6'位）、（R）-3-羟基十四烷酸（3位）和（R）-3-（十四烷酰氧基）十四烷酸（3'位）取代。C-4位的羟基似乎是游离的。二糖的氨基以特定分布带有（R）-3-（酰氧基）酰基[和（R）-3-羟基酰基]残基。基于这些数据，提出了脂质A的一般结构。作为这种一般结构的一个具体例子，给出了明尼苏达沙门氏菌LPS的脂质A的化学结构。
