Table 1.

Purification details of recombinant proteins used

Protein	Expression system	Lysis buffer	Ion-exchange column	Final buffer
His6-TEV-DCAF1(1039-1401)Q1250L	Sf9 insect cells	50 mM Tris pH 8.0, 200 mM NaCl, 0.1% Triton X-100, 4 mM TCEP	ResourceQ	20 mM Hepes pH 7.5, 200 mM NaCl, 2 mM TCEP
His-TEV-DCAF1(1079-1393)Q1250L	Sf9 insect cells	50 mM Tris pH 8.0, 200 mM NaCl, 0.1% Triton X-100, 4 mM TCEP	ResourceQ	20 mM Hepes pH 7.5, 200 mM NaCl, 2 mM TCEP
Avi_DCAF1(1073-1399)E1398S-His6	Sf9 insect cells Coexpressed with BirA	50 mM Tris (pH 8.0), 300 mM NaCl, 10% Glycerol (w/v), 5 mM TCEP, 5 mM Imidazole	Q HP	50 mM Tris, 300 mM NaCl, 10% Glycerol, 2 mM TCEP (pH 8.0)
DCAF1(1073-1399)E1398S-Avi-His6	Sf9 insect cells Coexpressed with BirA	50 mM Tris (pH 8.0), 300 mM NaCl, 10% Glycerol (w/v), 5 mM TCEP, 5 mM Imidazole	Q HP	50 mM Tris, 300 mM NaCl, 10% Glycerol, 2 mM TCEP (pH 8.0)
Strep-PreSc-DCAF1(987-1507)//DDB1(1-1140)//His-TEV-CUL4(38-759)//His-TEV-Rbx1(12-108)	Sf9 insect cells	50 mM Tris pH 8.0, 200 mM NaCl, 4 mM TCEP	ResourceQ	50 mM HEPES pH 7.4, 200 mM NaCl, and 0.25 mM TCEP
His_PreSc_BTK (389-659)	Sf9 insect cells	50 mM Tris pH 7.6, 400 mM NaCl, 10% Glycerol, 3 mM TCEP	ResourceQ	20 mM TrisHCl, 100 mM NaCl, 3 mM TCEP, 1 mM EDTA, pH 8.0
His_PreSc_Avi_Btk (389-659)	Sf9 insect cells Coexpressed with BirA	50 mM Tris pH 7.6, 400 mM NaCl, 10% Glycerol, 3 mM TCEP	ResourceQ	50 mM Tris pH 8.0, 200 mM NaCl, 5% Glycerol, 2 mM TCEP
GST-PreSc-BRD9 (130-250)	E.Coli	1x PBS pH 7.4, 400 mM KCl, 5 mM DTT, 1 mM MgCL2, 10% Glycerol, 1 mM PMSF	n/a	25 mM HEPES pH 7.5, 100 mM KCl, 5 mM DTT