Characterization crystallization and preliminary X-ray crystallographic analysis of the human Uba5 C-terminus–Ufc1 complex

摘要

Human Uba5, which contains an adenylation domain and a C-terminal region, is the smallest ubiquitin-like molecule-activating enzyme. The mechanism through which the enzyme recognizes Ufc1 and catalyzes the formation of the Ufc1–Ufm1 complex remains unknown. In this study, Uba5 residues 364–404 were demonstrated to be necessary for the transthiolation of Ufm1 to Ufc1, and Uba5 381–404 was identified to be the minimal region for Ufc1 recognition. The fusion protein between Uba5 381–404 and Ufc1 was cloned, expressed and purified, and exists as a homodimer in solution. Crystallization was performed at 293 K using PEG 4000 as precipitant; the optimized crystals diffracted to 3.0 Å resolution and had unit-cell parameters a = b = 82.49, c = 62.47 Å, α = β = 90, γ = 120°. With one fusion-protein molecule in the asymmetric unit, the Matthews coefficient and solvent content were calculated to be 2.55 ų Da⁻¹ and 51.84%, respectively.