Bacillithiol is an antioxidant thiol produced in Bacilli

Glutathione is a nearly ubiquitous, low-molecular-mass thiol and antioxidant, but it is conspicuously absent from most Gram-positive bacteria. We identify here the structure of bacillithiol, a newly described and abundant thiol produced by Bacillus species, Staphylococcus aureus and Deinococcus radiodurans . Bacillithiol is the α-anomeric glycoside of L -cysteinyl- D -glucosamine with L -malic acid and most probably functions as an antioxidant. Bacillithiol, like the structurally similar mycothiol, may serve as a substitute for glutathione.