Fig. 3: DNA- and ubiquitin-binding affect SPRTN’s conformation synergistically.
From: Allosteric activation of the SPRTN protease by ubiquitin maintains genome stability
a–f Comparison of NMR spectra, highlighting Trp ε1 amide signals in 1H,15N-HSQC experiments of SprT-BR and SprT-BR-L99S. Trp ε1 region is labeled and boxed (bottom). Resonance assignments corresponding to the Trp ε1’s in the zinc-binding domain (ZBD) are shown in orange and those in the protease domain in blue. Broadened or shifted signals upon dsDNA addition are shown as asterisk. a, b SprT-BR (a) and SprT-BR-L99S (b) alone (= Apo) (black), with mono-ubiquitin (Ub1) (5x molar excess) (red). Minor changes are boxed in blue to highlight the spectral differences between SprT-BR and SprT-BR-L99S upon adding Ub1. Zoom-in region in Supplementary Fig. 3e is marked with a black box (b). c, d SprT-BR (c) and SprT-BR-L99S (d) alone (black) (= Apo), with dsDNA (2x molar excess) (red). Some of the ZBD resonances affected by dsDNA are labeled in black while the unchanged are labeled in grey. e, f Superimpositions of SprT-BR (e) and SprT-BR-L99S (f) in the presence of dsDNA (2x molar excess) (black) and of both dsDNA (2x molar excess) and Ub1 (5x molar excess) (red). Additional resonance changes upon adding Ub1 to the dsDNA-bound SprT-BR are shown with red boxes.
