TATA-Binding Protein: Difference between revisions

The enzyme RNA polymerase performs the delicate task of unwinding the two strands of DNA and transcribing the genetic information into a strand of RNA. But how does it know where to start? Our cells contain 30,000 genes encoded in billions of nucleotides. For each gene, the cell must be able to start transcription at the right place and at the right time.

== Exploring the Structure ==

TATA-binding protein uses two types of interactions to recognize and hold the TATA sequence, as seen in this structure [[1ytb]]. First, as shown at the top, it has a string of lysine and arginine amino acids (colored dark blue) that interact with the <scene name='TATA-Binding_Protein/1ytb/2'>phosphate groups of the DNA</scene>. This glues the <scene name='TATA-Binding_Protein/1ytb/7'>protein</scene> to the <scene name='TATA-Binding_Protein/1ytb/6'>DNA</scene>. Second, the protein uses specially-placed amino acids to interact with DNA bases. <scene name='TATA-Binding_Protein/1ytb/8'>four phenylalanine amino acids</scene> jam into the DNA minor groove and form the kinks that bend the DNA. There are also <scene name='TATA-Binding_Protein/1ytb/9'> two symmetrical asparagine amino acids </scene> that form hydrogen bonds at the very center. The combination of the unusual flexibility of TATA DNA sequences and these specific hydrogen bonds allows TATA-binding protein to recognize the proper sequence.