Microbial sulfur-containing and disulfide-bonded proteins

Microbial sulfur-containing and disulfide-bonded proteins constitute a diverse and essential class of molecules required for the survival, structural integrity, and pathogenicity of bacteria, fungi, and viruses. These proteins rely on the reactive properties of sulfur-containing amino acids, primarily cysteine and methionine, to form disulfide bridges that stabilize protein tertiary and quaternary structures, particularly in the harsh extracytoplasmic environment (Heras et al., 2015, Nature Reviews Microbiology). In many bacterial pathogens, the Disulfide Bond (Dsb) system—including enzymes like DsbA and DsbB—is responsible for catalyzing the formation of these bonds, which are critical for the functional assembly of toxins, adhesins, and secretion systems (Landeta et al., 2018, Nature Communications). From a therapeutic perspective, these proteins are targeted by a variety of antimicrobial agents that exploit the high affinity of sulfur for certain metals and oxidants. For example, silver ions ($Ag^+$) exert potent antimicrobial effects by binding to thiol groups, leading to the denaturation of essential enzymes and the disruption of the microbial respiratory chain (Jung et al., 2008, Applied and Environmental Microbiology). Additionally, novel small-molecule inhibitors are being developed to specifically target the Dsb machinery as an anti-virulence strategy, aiming to disarm pathogens without necessarily killing them, which may reduce the selective pressure for antibiotic resistance (Halili et al., 2015, Journal of Molecular Biology).

Other names

Thiol-containing microbial proteinsCysteine-rich bacterial proteinsMicrobial disulfide bond (Dsb) system proteinsSulfhydryl-containing microbial enzymes

Drugs targeting these proteins typically act via the oxidation of sulfhydryl (thiol) groups, the formation of stable metal-mercaptide complexes, or the competitive inhibition of enzymes like DsbA and DsbB that catalyze disulfide bond formation, thereby preventing the correct folding of essential microbial proteins and virulence factors (Heras et al., 2015, Nature Reviews Microbiology; Jung et al., 2008, Applied and Environmental Microbiology).