Scientists have determined the atomic-level structure of an enzyme that plays a key role in switching genes on, providing insights into how some medicines work and paving the way for potential new treatments.

The structure of the enzyme, called TFIID, was revealed using a technique called cryo-electron microscopy, which allows researchers to visualize molecules in unprecedented detail.

TFIID is a complex of proteins that assemble at specific DNA sequences to initiate transcription, the process by which DNA is copied into RNA. RNA molecules are then translated into proteins, which are the workhorses of cells.

The structure shows how TFIID binds to DNA and opens it up so that other proteins can access and transcribe it. This process is essential for controlling gene expression and ensuring that cells produce the proteins they need.

TFIID is the target of several drugs, including the immunosuppressant cyclosporin A. The new structure could help researchers design new drugs that target TFIID more effectively and with fewer side effects.

The research was published in the journal Science Advances and was supported by the National Institutes of Health.

"Our structure of TFIID provides a detailed roadmap for how transcription starts at gene promoters, and it sets the stage for understanding the fundamental mechanisms by which transcription factors regulate gene expression." said study lead author Dr. Stephen Burley, a professor of biochemistry at the University of Texas Southwestern Medical Center.