The Role of Low Molecular Weight Thiols in Bacteria
In the cell, low molecular weight thiols are responsible for the reducing environment needed for biochemical reactions to occur, act as cofactors for various metabolic reactions, and protect the cell against oxidants and electrophiles. While glutathione is the major thiol in gram-negative bacteria and higher organisms, most gram-positive bacteria do not contain glutathione. In the high GC Actinomycetes, mycothiol substitutes for glutathione and we have recently demonstrated that bacillithiol is the major thiol in the low GC Firmicutes. A third thiol, ergothioneine, is found in almost all organisms but was previously thought to be synthesized only by fungi and Actinomycetes. These thiols differ in their chemical structure and thus it is possible that they serve complementary functions in the bacterial cell. One aspect of my research program concerns unique thiols of bacteria and the function of these thiols in the bacterial cell. We are especially interested in the role of thiols in coping with environmental stress, detoxification, and the contribution of these thiols to inherent drug resistance in bacteria. In addition, I am interested in the genes and enzymes involved in the biosynthesis and metabolism of these thiols and the potential of these genes and enzymes as novel drug targets.
We are examining the role of glutathione in Synechococcus PCC 7942, a unicellular, phototrophic, freshwater cyanobacterium and the role of glutathione and ergothioneine in Synechocystis PCC 6803, a unicellular freshwater cyanobacterium that can grow phototrophically and heterotropically.
