Expression, purification, and co‐crystallization of IRF‐I bound to the interferon‐β element PRD I

Abstract
Interferon regulatory factor 1 (IRF‐1) is an essential factor involved in the regulation of type I interferon (IFN) and IFN‐inducible genes. The protein consists of 329 amino acids that are highly conserved from mouse to human. Similar to other transcription factors, the protein is modular in nature with a basic N‐terminal region involved in DNA binding and an acidic C‐terminal region required for activation. We report here the expression, purification and co‐crystallization of the minimal N‐terminal region of IRF‐1 involved in DNA binding (amino acids 1–113) with a 13 bp DNA fragment from the IFN‐β promoter. The crystals diffract to at least 3.0Åin resolution and belong to space group R3 with unit cell parameters of a = b = 84.8Å, c = 203.7Å.