Practice question

TBP abbreviates TATA-box binding protein, a twenty-seven kilodalton highly conserved universal transcription factor with saddle-shaped twofold symmetry, binding DNA as monomer. It inserts conserved phenylalanine residues into minor groove of TATA box, deforming DNA and providing landmark for preinitiation complex assembly. Present in TFIID for Pol II, SL1 for Pol I, and TFIIIB for Pol III, making it central to all three nuclear polymerase systems. TBP interacts with TFIIA, TFIIB, TAFs, and activators, nucleating transcription complex formation and promoter selection.