Microbial cell wall primary amine groups

Microbial cell wall primary amine groups are essential chemical moieties found within the structural matrix of bacteria and fungi. In bacteria, these amines are typically located on the side chains of amino acids like L-lysine (in many Gram-positives) or meso-diaminopimelic acid (in Gram-negatives) within the peptidoglycan layer, where they serve as nucleophilic acceptors in the transpeptidation reaction required for cell wall cross-linking. In fungi, primary amines are prominent in deacetylated chitin, known as chitosan. These groups are critical for maintaining the structural integrity and mechanical strength of the cell wall, making them vital for microbial survival. Therapeutically, they are targeted indirectly by major antibiotic classes like beta-lactams and glycopeptides, which disrupt the cross-linking process, and directly by chemical disinfectants like glutaraldehyde that cause lethal protein and wall cross-linking. Additionally, the cationic nature of these amines at physiological pH is exploited by antimicrobial peptides and polymers for selective binding to microbial surfaces.

Other names

Bacterial surface aminesPeptidoglycan amino groupsCell wall amino groupsL-Lysine/m-DAP amine groupsChitosan primary amines

These groups serve as nucleophilic acyl-acceptors in the transpeptidation reaction catalyzed by penicillin-binding proteins (PBPs), which is essential for peptidoglycan cross-linking. Drugs like beta-lactams inhibit the PBPs, while glycopeptides like vancomycin sequester the D-Ala-D-Ala substrate to prevent amine attack. Chemical agents like glutaraldehyde covalently cross-link these amines to induce microbial death.