lipid A biosynthetic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the formation of lipid A, the glycolipid group of bacterial lipopolysaccharides, consisting of four to six fatty acyl chains linked to two glucosamine residues. Further modifications of the backbone are common. [ISBN:0198506732, PMID:20974832, PMID:22216004]

Lipid A biosynthesis is a complex process that occurs in the outer membrane of Gram-negative bacteria. It involves the assembly of a highly conserved glycolipid known as lipid A, which is the anchor for the lipopolysaccharide (LPS) molecule that is essential for bacterial survival. The process starts with the synthesis of UDP-glucosamine, which is then converted to UDP-N-acetylglucosamine (UDP-GlcNAc). Two molecules of UDP-GlcNAc are then linked together to form UDP-GlcNAc-(β1→6)-GlcNAc, a disaccharide precursor. This disaccharide is then transferred to a lipid carrier molecule, undecaprenyl phosphate (UndP), forming the first lipid intermediate. The lipid A biosynthesis pathway then involves the addition of fatty acyl chains to the disaccharide. The first fatty acyl chain is added to the N-acetylglucosamine residue at position 3, followed by the addition of a second fatty acyl chain at position 2. This process is repeated on the other N-acetylglucosamine residue, resulting in a tetra-acylated disaccharide. The next step involves the addition of two additional fatty acyl chains, one at position 2 and one at position 3, forming a hexa-acylated disaccharide. This hexa-acylated disaccharide is then further modified by the addition of a phosphate group at position 1, resulting in a complete lipid A molecule. The lipid A molecule is then incorporated into the outer membrane, where it serves as the anchor for the LPS molecule.'
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Proteins (2)

Compounds (4)