TATA-Binding Protein: Difference between revisions

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== Exploring the Structure ==
== 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 phosphate groups of the DNA (colored bright yellow and red). This glues the protein to the DNA. Second, the protein uses specially-placed amino acids to interact with DNA bases. As shown in the lower picture, four phenylalanine amino acids jam into the DNA minor groove and form the kinks that bend the DNA. There are also two symmetrical asparagine amino acids 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.
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/1'>phosphate groups of the DNA</scene>. This glues the protein to the DNA. Second, the protein uses specially-placed amino acids to interact with DNA bases. As shown in the lower picture, four phenylalanine amino acids jam into the DNA minor groove and form the kinks that bend the DNA. There are also two symmetrical asparagine amino acids 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.


As you are looking at these structures yourself, notice that TATA-binding protein, even though it is composed of a single protein chain, is composed of two symmetrical halves. This symmetry is easily seen in the two pairs of phenylalanines and the two asparagines shown in the lower figure. It is thought that an ancient gene duplication created this protein by combining two copies of the same gene.  
As you are looking at these structures yourself, notice that TATA-binding protein, even though it is composed of a single protein chain, is composed of two symmetrical halves. This symmetry is easily seen in the two pairs of phenylalanines and the two asparagines shown in the lower figure. It is thought that an ancient gene duplication created this protein by combining two copies of the same gene.