Glutathione is a nearly ubiquitous low-molecular-weight thiol and antioxidant, although it is conspicuously absent from most Gram-positive bacteria. We identify here the structure of bacillithiol, a novel 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 likely functions as an antioxidant. Bacillithiol, like structurally similar mycothiol, may serve as a substitute for glutathione.

Actinomycetes produce mycothiol as their major low molecular weight thiol, which parallels the functions of glutathione found in prokaryotes and most Gram-negative bacteria. This review covers progress that has so far been made in terms of its distribution, biosynthesis and metabolic functions, as well as chemical syntheses of mycothiol and alternative substrates and inhibitors of mycothiol biosynthesis and mycothiol-dependent enzymes. 152 references are cited.

The full monty: The recently discovered thiol cofactor bacillithiol (BSH), its biosynthetic precursors, and its symmetrical disulfide are prepared in two ways. The fosfomycin resistance protein (FosB) is shown to be a BSH‐utilizing enzyme. It displays bacillithiol‐S‐transferase activity with a strong preference for BSH over L‐cysteine as its thiol substrate.

Das volle Programm: Der kürzlich entdeckte Thiol‐Cofaktor Bacillithiol (BSH), seine Biosynthesevorstufe und sein symmetrisches Disulfid wurden auf zwei Arten hergestellt. Das Fosfomycinresistenzprotein (FosB) zeigt BSH‐S‐Transferaseaktivität mit einer starken Bevorzugung von BSH gegenüber L‐Cystein als Thiolsubstrat.

A solid phase synthesis of des-myo-inositol mycothiol disulfide and its alpha-configured methyl- and benzyl-glycoside derivatives has been developed. Kinetic characterisation of these compounds has demonstrated their viability as alternative substrates for use in mycothiol disulfide reductase enzyme assays.