Three-Dimensional Structure of Recombinant Human Interferon-γ

The x-ray crystal structure of recombinant human interferon-γ has been determined with the use of multiple-isomorphous-replacement techniques. Interferon-γ, which is dimeric in solution, crystallizes with two dimers related by a noncrystallographic twofold axis in the asymmetric unit. The protein is primarily α helical, with six helices in each subunit that comprise ~62 percent of the structure; there is no β sheet. The dimeric structure of human interferon-γ is stabilized by the intertwining of helices across the subunit interface with multiple intersubunit interactions.