A model of the three-dimensional structure of human interferon responsive factor 1 and its modifications upon phosphorylation or phosphorylation-mimicking mutations

AbstractInterferon responsive factor 1 (IRF-1) is a pleiotropic transcription factor, possessing non-redundant biological activities that depend on its interaction with different protein partners and multiple post-translational modifications including phosphorylation. In particular, a 5′-SXXXSXS-3′ motif of the protein represents the target of the IκB-related kinases, TANK-binding kinase (TBK)-1 and inhibitor of nuclear factor kappa-B kinase (IKK)-e. Here, a 3D model of human IRF-1 was determined by using multi-template comparative modeling and molecular dynamics approaches. Models obtained through either phosphorylation or aspartate mutation of residues 215, 219 and 221 were also calculated and compared to the wild type. Calculations indicated that each of these modifications mainly induces a rigidification of the protein structure and only slightly changes in electrostatics and hydrophobicity of IRF-1 surface, resulting in the impairment of the capacity of IRF-1 containing as partate mutations (S221D an...