Bacterial proteins containing thiol groups

Bacterial proteins containing thiol groups represent a broad class of targets for various antimicrobial agents, most notably heavy metal ions like silver and mercury. These proteins include a wide array of essential enzymes and structural components that utilize the sulfhydryl (-SH) group of cysteine residues for catalytic activity or structural stability (Medici et al., 2019). When silver ions or mercurial compounds enter the bacterial cell, they exhibit a high affinity for these soft sulfur donors, forming stable covalent bonds that displace natural ligands or disrupt disulfide bridges. This interaction results in the widespread denaturation of proteins, inhibition of key metabolic pathways such as glycolysis and the citric acid cycle, and the impairment of cellular respiration (Peana et al., 2021). For example, silver ions have been shown to specifically target and inactivate glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in Escherichia coli. Consequently, the bacteria lose their ability to maintain homeostasis and replicate, leading to potent bacteriostatic or bactericidal effects. While highly effective as topical antiseptics and disinfectants, the lack of specificity for bacterial versus host thiols necessitates careful application to avoid systemic toxicity or localized tissue damage (StatPearls, 2023).

Other names

Bacterial sulfhydryl-containing proteinsBacterial thiol-containing proteinsBacterial sulfhydryl groupsBacterial thiol-containing enzymesBacterial cysteine-containing proteins

Antimicrobial agents, particularly heavy metal ions like silver (Ag+) and mercury (Hg2+), exert their effects by binding covalently to the sulfur atoms of thiol (sulfhydryl) groups in bacterial proteins (Medici et al., 2019). This interaction leads to the displacement of essential metal cofactors, the disruption of disulfide bridges, and the denaturation of structural proteins. Furthermore, the binding inactivates critical enzymes involved in the glycolytic pathway, such as glyceraldehyde-3-phosphate dehydrogenase, and components of the electron transport chain, effectively halting bacterial metabolism and respiration (Peana et al., 2021).