Transcription activation complex analyzed
STU BORMAN · C&EN Global Enterprise · 2016
To better understand how DNA is transcribed into RNA, scientists have long been trying to obtain a detailed structure of a protein-DNA complex that initiates and regulates transcription of a specific gene. But such complexes have been hard to crystallize. Richard H. Ebright and coworkers at Rutgers University have now found a thermophilic bacterial complex that forms crystals readily and have determined its 4.4-Å structure (Science 2016, DOI: 10.1126/science.aaf4417). The complex includes a transcription activator protein, an initiation factor, RNA polymerase, a DNA template, and an RNA primer. The crystal structure reveals that a first set of protein-protein interactions between the activator and RNA polymerase helps the enzyme bind DNA and a second set of protein-protein interactions helps the enzyme unwind DNA so it can be transcribed. “It’s a lovely picture that you can tell is right” from decades of earlier biochemistry and genetics experiments on similar transcription activation complexes,