Steric configuration-enabled selective antimicrobial activity of chiral cysteine.

Antibiotics abusing caused multi-drug resistant bacteria was an urgent need to develop effective alternatives to antibiotics. L-Cysteine is an amino acid commonly found in organisms, which is usually used as food additive and detoxication, while the antibacterial activity of L-Cysteine against pathogenic bacteria is rarely reported. Here, we demonstrated the broad-spectrum and selected antibacterial properties of D-/L-Cysteine, for the first time, D-Cysteine (D-Cys) and L-Cysteine (L-Cys) exhibited distinct antibacterial activity based on different bacteria (Escherichia coli, Staphylococcus aureus, Listeria monocytogenes and Salmonella enteritis). Among the four bacteria, L-Cys exhibited preferred antibacterial activity against S. aureus, while D-Cys showed stronger antibacterial activity against other three bacteria compared with L-Cys. Through analyzing cell structure of E. coli, it was demonstrated that D/L-Cys could destroy the integrity of E. coli cell membrane, which further resulted in the leakage of cell contents and cell death. This work has a potential value for the development of chiral bacteriostatic materials.