cI Protein From Lambda Phage

cI Protein From Lambda Phage

CPK Color Scheme

Click this button to make the DNA go away and focus on the secondary structure of the two identical cI subunits of this dimer. Notice that the DNA-binding domain contains only alpha helices and the protein interaction domain contains only beta strands.

Click this button to show the cI dimer in spacefill view as purple and orange molecules, and the DNA as a blue and red double helix. You will be able to see through the minor groove of the DNA which tells you that the alpha helices are binding to the DNA one in the major groove.

Click here to see the amino acids that reach into the major groove and determine the binding affinity of cI for operator 1.

Click here to focus on the dimerization of the cI proteins. You are looking at the reason cI forms dimers and can produce cooperativity between a pair of dimers binding to operator 1 and operator 2.


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