DNA-protein interactions: Difference between revisions
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== Helix-Turn-Helix Interactions with DNA== | == Helix-Turn-Helix Interactions with DNA== | ||
The first DNA binding domain characterized was the helix-turn-helix. In helix-turn-helix protein, two α helices are joined by a turn. In most cases | The first DNA binding domain characterized was the helix-turn-helix. In a <scene name='71/711660/Protein_rainbow/1'>helix-turn-helix protein</scene> such as the Cro repressor, two α helices are joined by a turn; there may be additional supporting structures, such as additional helices or beta strands, but this is the basic motif. In most cases, the <scene name='71/711660/C_terminal_helix/1'>C terminal helix</scene> contributes most to DNA recognition, and hence it is often called the "recognition helix". It binds to the major groove of DNA through a series of hydrogen bonds and various Van der Waals interactions with exposed bases. For example, Asn51 forms hydrogen bonds with both A219 and A220 of the DNA strand. The N-terminal alpha helix stabilizes the interaction between the interaction between protein and DNA, but does not play a particularly strong role in its recognition.[2] The recognition helix and its preceding helix always have the same relative orientation.[ | ||
== Leucine zippers == | == Leucine zippers == | ||
