DNA-protein interactions: Difference between revisions

<scene name='71/711660/Gal4/1'>GAL4</scene> is a transcription factor that induces genes required for the metabolism of galactose, specifically enzymes involved in the conversion of galactose to glucose, and is an example of a zinc finger DNA binding protein.  The protein binds as a <scene name='Taylor_Gal4_Sandbox/Dimer/1'>dimer</scene> to a symmetrical 17-base-pair sequence.  Each subunit folds into three distinct modules:  a compact, <scene name='Taylor_Gal4_Sandbox/Metal_binding_domain/2'>metal binding domain</scene>(residues 8-40), an extended <scene name='Taylor_Gal4_Sandbox/Linker/1'>linker</scene>(41-49), and an <scene name='Taylor_Gal4_Sandbox/Dimerization/1'>alpha-helical dimerization element</scene> (50-64).  The small, <scene name='Taylor_Gal4_Sandbox/Zn_binding/1'>Zn(2+)-containing domain</scene>, which contains two metal ions tetrahedrally coordinated by six cysteines. This metal binding domain recognizes a conserved CCG triplet at each end of the site through direct contacts with the <scene name='Taylor_Gal4_Sandbox/Major_groove/1'>major groove</scene>. A short coiled-coil dimerization element imposes 2-fold symmetry. A segment of extended polypeptide chain links the metal-binding module to the dimerization element and specifies the length of the site. The relatively open structure of the complex would allow another protein to bind coordinately with GAL4.