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 ) Structure of the binding interface between the UFD of S. pombe Uba1 (interacting residues colored pink) and the alpha-1 helix (aa 1–18, colored by amino acid property) of the E2 Ubc15 (cyan), as revealed by the x-ray structure of the S. pombe Uba1/Ubc15 complex (PDB: 5KNL) . ( b ) Amino acid sequences of the SAH-Ubc15 E7R staple-scanning library, which was generated by inserting all-hydrocarbon i, i+4 or i, i+7 staples sequentially along the length of the Ubc15 E7R peptide. X, S5-pentenyl alanine; 8, R5-octenyl alanine; B, norleucine (replacement for methionine, whose sulfur residue decreases the efficiency of ruthenium-catalyzed olefin metathesis). ( c ) Helical wheel depiction of SAH-Ubc15 E7R peptides and their staple positions (helical residues span from aa 5–18). ( d ) Inhibition of UBE1-mediated thioester transfer of ubiquitin to the E2 enzyme UBE2D2 by the indicated SAH-UBC15 E7R stapled peptides. Thioester transfer activity was monitored by the shift in E2 molecular weight from 17 kDa (free UBE2D2) to 25 kDa (UBE2D2~ubiquitin conjugate), as detected by gel electrophoresis and silver stain. Vehicle lane contained 1.5% DMSO and control lane lacked UBE1 protein. The bar graph represents mean inhibition relative to vehicle control ± s.e.m., as quantified and averaged across three independent biological replicates. Uncropped gel for panel d is available online. Source data for the thioester transfer assay plot is 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: Binding Assay, Generated, Residue, Inhibition, Ubiquitin Proteomics, Activity Assay, Molecular Weight, Nucleic Acid Electrophoresis, Silver Staining, Control

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

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) Sequence compositions of the unmodified UBE2A template peptide and stapled constructs SAH-UBE2A, SAH-UBE2A R7E , and SAH-UBE2A R7A/L9A/B10A . (b) Comparative effects of UBE2A, SAH-UBE2A, SAH-UBE2A R7E , and SAH-UBE2A R7A/L9A/B10A on UBE1-mediated thioester transfer of ubiquitin to the E2 enzyme UBE2D2. Whereas SAH-UBE2A (10 μM) completely inhibits UBE1 activity, triple mutagenesis abrogates the inhibitory effect and single R7E mutagenesis has an intermediate effect. (c) Progressive loss of UBE1 protection from deuterium exchange into SAH-UBE2A upon single R7E and triple R7A/L9A/B10A mutagenesis. 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 each SAH-UBE2A peptide 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. (d) Difference in deuterium uptake plots demonstrate the relative deuterium incorporation of SAH-UBE2A/UBE1, SAH-UBE2A R7E /UBE1, or SAH-UBE2A R7A/L9A/B10A /UBE1 minus the relative deuterium incorporation of UBE1 at 10 min of deuterium labeling. The shaded gray region indicates differences in deuteration that are below the meaningful differences threshold. Consistent with results of both the thioester transfer assay (b) and peptide deuterium exchange (c), and the predicted SAH-UBE2A/UBE1 binding mode, triple mutagenesis essentially abrogates the effect of SAH-UBE2A on UBE1 conformation, with single R7E mutagenesis having an intermediate influence. Data are representative of three independent replicates for SAH-UBE2A, and two independent replicates for SAH-UBE2A R7E and SAH-UBE2A R7A/L9A/B10A . Each peptide, from N- to C-terminus, was given a peptide number to simplify the presentation. The peptide list and residue identity of each peptide can be found in . Uncropped gel for panel b is available online. Source data for the HXMS analyses 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: Sequencing, Construct, Ubiquitin Proteomics, Activity Assay, Mutagenesis, Labeling, Binding Assay, Residue