Journal: Nature chemical biology
Article Title: Targeting a Helix-in-Groove Interaction Between E1 and E2 Blocks Ubiquitin Transfer
doi: 10.1038/s41589-020-0625-7
Figure Lengend Snippet: ( a ) Amino acid sequences of stapled peptides corresponding to the N terminus and alpha-1 helix of UBE2D2 (aa 1–16), UBE2G2 (aa 1–14), and UBE2A (aa 1–17), which incorporate the optimal staple position identified for SAH-Ubc15–11. X, S5-pentenyl alanine; 8, R5-octenyl alanine; B, norleucine. ( b ) Comparative dose-responsive inhibition of UBE1 by the indicated SAH-E2 h1 peptides, as monitored by thioester transfer assay, gel electrophoresis, and silver stain. ( c ) Quantitation of the data in b by ImageJ analysis. Data are mean percent inhibition ± s.e.m. for three independent biological replicates. ( d ) Circular dichroism spectra of UBE2A (BSTPARRRLBRDFKRLQ, where B is norleucine) and SAH-UBE2A, demonstrating induction of α-helicity by insertion of the i, i+7 staple. ( e ) Inhibition of UBE1-mediated thioester transfer of ubiquitin to the E2 enzyme UBE2D2 by SAH-UBE2A but not the corresponding unmodified template peptide, UBE2A. Data are mean inhibition ± s.e.m. for three independent biological replicates. ( f ) Comparative protease resistance of SAH-UBE2A and UBE2A upon treatment with proteinase K, as measured by HPLC analysis. SAH-UBE2A displays a 23-fold longer half-life than UBE2A. Data are mean ± s.d. for experiments performed in triplicate. ( g ) SAH-UBE2A but not UBE2A was significantly protected from deuterium exchange upon incubation with UBE1. The relative difference in deuterium uptake after 10 sec of labeling is shown. The difference in uptake was calculated from the mean deuterium level for UBE2A or SAH-UBE2A in the presence of UBE1 minus that of the peptide alone. Mean deuterium levels were obtained from at least two independent biological replicates of each condition. ( h ) C-terminally biotinylated SAH-UBE2A directly bound to recombinant human UBE1 (MW 118 kDa), as demonstrated by streptavidin capture, gel electrophoresis, and silver stain. ( i ) C-terminally FITCylated SAH-UBE2A bound to UBE1 with a K d of 384 ± 43 nM, as assessed by fluorescence polarization assay. Error bars are s.d. for assays conducted in technical triplicate and performed three times with independent preparations of peptide and protein (all 9 points for each dosing level are plotted). Uncropped gels for panels b , e , and h are available online. Source data for thioester transfer assays, CD spectra, protease resistance testing, HXMS analyses, and FP plot are available online.
Article Snippet: For UBA3 thioester transfer assays, 15 nM NAE1/UBA3 was substituted for UBE1 (Boston Biochem E-313), 135 nM UBE2M for UBE2D2 (Boston Biochem E2–656), and 1 μM NEDD8 (Boston Biochem UL-812) for ubiquitin.
Techniques: Inhibition, Nucleic Acid Electrophoresis, Silver Staining, Quantitation Assay, Circular Dichroism, Ubiquitin Proteomics, Incubation, Labeling, Recombinant, Fluorescence