Transcription activation complex analyzed in high-def

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, comments transcription initiation expert Deborah M. Hinton of the National Institute of Diabetes & Digestive & Kidney Diseases.