Two teams of researchers at Rutgers, The State University of New Jersey, discovered independently that MccJ25 uniquely blocks a "tunnel" into the bacterial enzyme, RNA polymerase (RNAP). The "tunnel" is used to bring raw materials for RNA synthesis into the enzyme and to expel byproducts of RNA synthesis.
"Closing the crowded, two-way 'tunnel' starves RNAP, shuts it down and kills the bacteria," said Richard H. Ebright, a Howard Hughes Medical Institute investigator, and a professor in Rutgers' department of chemistry and chemical biology and the Waksman Institute of Microbiology. "Understanding the way in which MccJ25 works sets the stage for the development of novel antibacterial drug designs."
To understand how MccJ25 works, Ebright's group used genetic methods to test hundreds of thousands of RNAP derivatives, or variants, in order to define the binding sites for MccJ25 on RNAP. The researchers also used biophysical methods, attaching fluorescent tags to MccJ25 and to each of a dozen sites in RNAP. Using the tags, the researchers gauged the position of each bound pair in a GPS-like manner, verifying the results of the genetic work. They then used biochemical methods to find out what happened once MccJ25 binds to the RNAP.
The research team of Konstantin Severinov, an associate professor in Rutgers' department of molecular biology and biochemistry and the Waksman Institute, had been the first to demonstrate that RNAP from cells resistant to MccJ25 also showed resistance to the drug in a test tube. In their current work, these researchers used biochemical methods to characterize, in molecular detail, the mechanism of MccJ25 action. In
Contact: Joseph Blumberg
Rutgers, the State University of New Jersey