Final answer:
Activator proteins bind to enhancer sequences, resulting in DNA bending and increasing RNA polymerase affinity for the promoter, enhancing transcription initiation.
Step-by-step explanation:
Some activators bind to enhancer sequences near the promoter site resulting in DNA conformation with increased affinity for RNA polymerase. Activator proteins bind to enhancer regions, which may be located at a significant distance from the promoters. The DNA must bend to bring the activator protein in contact with the promoter. This is facilitated by DNA bending proteins, which change the shape of the DNA, enhancing the interaction between the activators and the transcription initiation complex, thereby increasing the affinity of RNA polymerase to the promoter region for transcription initiation.
Within the promoter region, the TATA box is a critical element where the first transcription factor, TFIID, binds. This binding event attracts additional transcription factors and positions the RNA polymerase properly to initiate transcription. The presence of activator proteins bound to enhancer sequences and their interaction with promoter-bound transcription factors greatly enhances the efficacy of transcription initiation.