ANP32B, Acidic leucine-rich nuclear phosphoprotein family member B; BTFA, 3-bromo-1,1,1-trifluoroacetone; CD, Circular dichroism; CDK9, Cyclin-dependent kinase 9; CW, Continuous wave; Cc, Cytochrome c; Cytochrome c; DDR, DNA damage response; DEER, Double electron­electron resonance; DLS, Dynamic light scattering; DMEM, Dulbecco's modified Eagle's medium; DNA, Deoxyribonucleic acid; DTT, Dithiotreitol; Dmax, Maximum dimension; EDTA, Ethylenediamine tetraacetic acid; EGTA, Ethyleneglycol tetraacetic acid; EPR, Electron paramagnetic resonance; Encounter complex; FBS, Fetal bovine serum; GUI, Graphical user interface; HEK, Human embryonic kidney cells; HRP, Horseradish peroxidase; I2PP2A, Inhibitor 2 of the protein phosphatase 2A; I3PP2A, Inhibitor 3 of the protein phosphatase 2A; INTAC, Integrator-PP2A complex; IPTG, Isopropyl-ß-D-1-thiogalactopyranoside; ITC, Isothermal titration calorimetry; Ip/Id, Intensity ratio of NMR resonances between paramagnetic and diamagnetic samples; LB, Luria-Bertani; MD, Molecular dynamics; MTS, (1-acetoxy-2,2,5,5-tetramethyl-δ-3-pyrroline-3-methyl) methanethiosulfonate; MTSL, (1-oxyl-2,2,5,5-tetramethyl- δ −3-pyrroline-3-methyl) methanethiosulfonate; MW, Molecular weight; Molecular dynamics; NAP1, Nucleosome assembly protein 1; NAPL, Nucleosome assembly protein L; NMA, Normal mode analysis; NMR, Nuclear magnetic resonance; NPT, Constant number, pressure and temperature; NVT, Constant number, volume and temperature; Nuclear magnetic resonance; OD600, Optical density measured at 600 nm; OPC, Optimal 3-charge, 4-point rigid water model; PCR, Polymerase chain reaction; PME, Particle mesh Ewald; PMSF, Phenylmethylsulfonyl fluoride; PP2A, Protein phosphatase 2A; PRE, Paramagnetic relaxation enhancement; PVDF, Polyvinylidene fluoride; Protein phosphatase 2A; RNA, Ribonucleic acid; RNApol II, RNA polymerase II; Rg, Radius of gyration; SAXS, Small-angle X-ray scattering; SC, Sample changer; SDS-PAGE, Sodium dodecylsulfate-polyacrylamide gel electrophoresis; SDSL, Site-directed spin labeling; SEC, Size-exclusion chromatography; SET/TAF-Iß; SET/TAF-Iß ΔC, SET/template-activating factor-Iß construct lacking its C-terminal domain; SET/TAF-Iß, SET/template-activating factor-Iß; SPRi, Surface plasmon resonance imaging; TAF-Iα, Template-activating factor-Iα; TPBS, Tween 20-phosphate buffered saline; VPS75, Vacuolar protein sorting-associated protein 75; WT, Wild type; XRD, X-ray diffraction