Preliminary X-ray crystallographic studies of the TRAF domain of human TRAF4

TNF receptor-associated factor (TRAF) proteins were initially identified as tumour necrosis factor receptor (TNFR)-interacting proteins that perform critical functions in the regulation of inflammation, antiviral responses and apoptosis. Although TRAF4 is a canonical TRAF protein, it contains a unique domain boundary and functions differently in the cell. In this study, the human TRAF4 TRAF domain, corresponding to amino acids 290–470, was overexpressed in Escherichia coli using engineered C-terminal His tags. The TRAF4 TRAF domain was then purified to homogeneity and crystallized at 293 K. Finally, X-ray diffraction data were collected to a resolution of 2.3 Å from a crystal belonging to space group P2₁2₁2₁, with unit-cell parameters a = 58.9, b = 87.9, c = 117.3 Å, α = β = γ = 90°.