TATA box
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A TATA box is a DNA sequence (cis-element) found in the promoter region of most genes (it is considered to be a promoter sequence). It is the binding site of either transcription factors or histones (binding of one blocks binding of the other). It has the DNA sequence 5' TATAAA(A/G) 3'.
In eukaryotes, it is normally bound by the TATA-binding protein (TBP), which melts the DNA, and bends it through 90°. The AT-rich sequence facilitates easy melting. The TBP is an unusual protein in that it binds the minor groove and binds with a β sheet.
Many genes lack a TATA box and use an initiator element or downstream core promoter instead.
Location
Found in the promoter region of most genes, about 25 base pairs upstream from the start site of transcription. It is usually adjacent to GC rich sequences.
Binding of histones
The binding of histones involves the N-terminal tail of H4.