A 2.2 Å resolution structure of the USP7 catalytic domain in a new space group elaborates upon structural rearrangements resulting from ubiquitin binding

New crystallization conditions for the catalytic domain of human ubiquitin specific protease 7 (USP7_CD) were found that produced crystals in space group C2 with one molecule in the asymmetric unit which is an advantage over previous crystallization conditions of USP7_CD which produced crystals in space group P2₁ with two molecules in the asymmetric unit. Comparison of the refined structure of USP7_CD in space group C2 with that of P2₁ suggests that conformational rearrangement of blocking loop residues 410-419 must occur in order for ubiquitin to bind and that the catalytic triad and switching loop region are in the same catalytically unproductive conformations as in the P2₁ structure in the absence of ubiquitin.