title: Bacillithiol, a new role in buffering intracellular zinc.
abstract: Zinc is a catalytic or structural cofactor of numerous proteins but can also be toxic if cells accumulate too much of this essential metal. Therefore, mechanisms of zinc homeostasis are needed to maintain a low but adequate amount of free zinc so that newly translated zinc-dependent proteins can bind their cofactor without confounding issues of toxicity. These mechanisms include the regulation of uptake and efflux transporters and buffering of the free metal concentration by low-molecular-weight ligands in the cytosol. While many of the transporters involved in zinc homeostasis have been discovered in recent years, the molecules that buffer zinc have remained largely a mystery. In the new report highlighted by this commentary, Ma et al. (2014) provide convincing evidence that bacillithiol, the major low-molecular-weight thiol compound in Bacillus subtilis, serves as an important zinc buffer in those cells. Their discovery provides an important piece to the puzzle of how zinc buffering occurs in a large number of microbes and provides new clues about the role and relative importance of zinc buffering in all organisms.
authors.affiliation: Department of Nutritional Sciences, University of Wisconsin-Madison, 1415 Linden Drive, Madison, WI, 53706, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Eide
mesh_terms: D001412:Bacillus subtilis / Q000378:metabolism*; D003545:Cysteine / Q000031:analogs & derivatives*; D005944:Glucosamine / Q000031:analogs & derivatives*; D015032:Zinc / Q000378:metabolism*
chemical_list: D015032:Zinc; D003545:Cysteine; D005944:Glucosamine