Assay Method Information

Assay Name:  Nedd8 Conjugation Inhibitory Activity
Description:  A purified NAE (heterodimer of APPBP1 and UBA3) solution was prepared in the following manner. The human APPBP1 gene (NCBI Reference Sequence number: NM_003905) region corresponding to amino acids 1 to 534 of human APPBP1 protein (NCBI Reference Sequence number: NP_003896, full length: 534 amino acids) was inserted in pBacPAK9 (produced by Clontech) to construct a plasmid pBacPAK9-APPBP1 for expressing APPBP1 full-length protein having a His tag and a TEV protease-recognition sequence at the N-terminus. Next, the human UBA3 gene (NCBI Reference Sequence number: NM_003968) region corresponding to amino acids 1 to 463 of human UBA3 protein (NCBI Reference Sequence number: NP_003959, full length: 463 amino acids) was inserted in pBacPAK9 to construct a plasmid pBacPAK9-UBA3 for expressing UBA3 full-length protein. The pBacPAK9-APPBP1 or pBacPAK9-UBA3, and BacPAK6 DNA were cotransfected into insect cells (Sf9, produced by Clontech) to produce a recombinant baculovirus containing APPBP1 or UBA3 gene. The APPBP1 gene recombinant baculovirus was mixed with the UBA3 gene recombinant baculovirus, and the resulting mixture was used to infect Sf9 cells. The baculovirus-infected Sf9 cells were incubated at 28° C. with shaking for 72 hours in Grace's Insect Medium (produced by Gibco), and the collected cells were suspended in a lysis buffer (50 mM Tris-HCl, 200 mM NaCl, and 10% glycerol (pH 7.4)), followed by sonication. The sonicated cell solution was centrifuged (40,000×g, for 30 minutes) to obtain the supernatant as a crude extract. The crude extract was fractionated on a HisTrap HP column (produced by GE Healthcare) and a TALON Superflow column (produced by Clontech), followed by the addition of a TEV protease. Then, a His-tag cleavage reaction was performed at 4° C. overnight. The resulting solution was subjected to TALON Superflow column chromatography, and the unadsorbed fraction was collected. This fraction was applied to a HiLoad 16/60 Superdex 75 prep grade column equilibrated with 50 mM Tris-HCl, 200 mM NaCl, and 10% glycerol (pH 7.4), and fractionated. A fraction containing an APPBP1/UBA3 complex was concentrated to obtain a purified NAE solution. The purification above was performed entirely at 4° C. The purified NAE solution was stored at −80° C. until use.A purified GST-UBC12 solution was prepared in the following manner. The human UBC12 gene (NCBI Reference Sequence number: NM_003969) region corresponding to amino acids 1 to 183 of human UBC12 protein (NCBI Reference Sequence number: NP_003960, full length: 183 amino acids) was inserted in pGEX-4T-2 (produced by GE Healthcare) to construct a plasmid pGEX-UBC12 for expressing UBC12 full-length protein having a GST tag at the N-terminus. The pGEX-UBC12 was introduced into Escherichia coli (BL21 (DE3), produced by Stratagene), followed by culture at 37° C. for 2 hours in the presence of 1 mM isopropyl-beta-D-thiogalactopyranoside (produced by Sigma-Aldrich). The collected Escherichia coli was suspended in PBS, followed by sonication. The sonicated cell solution was centrifuged (40,000×g, for 5 minutes) to obtain the supernatant as a crude extract. A Glutathione Sepharose 4B carrier (produced by GE Healthcare) was added to the crude extract, and eluted with 50 mM Tris-HCl (pH 7.9), 150 mM NaCl, and a 10 mM reduced glutathione solution, followed by dialysis with 50 mM HEPES (pH 7.5) and a 0.05% BSA solution to obtain a purified GST-UBC12 solution. The purified GST-UBC12 solution was divided and stored at −80° C. until use.The Nedd8 conjugation inhibitory activity was measured using an AlphaScreen assay system. Each of the purified NAE solution and GST-UBC12 solution was diluted with an assay buffer (50 mM HEPES (pH 7.5), 5 mM MgCl2, 1 mM DTT, 0.05% BSA) and added to a 384-well plate (#3673, produced by Corning) containing the test compound. After reaction at room temperature for 30 minutes, a solution obtained by diluting ATP and Biotin-Nedd8
Affinity data for this assay
 

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