Sandbox Reserved 431: Difference between revisions

The binding of Vitamin D3 occurs in a channel between the G and I helices and B' helix and B-C loop. In the <scene name='48/483888/Spacefilled_binding_site/1'>Space filling representation </scene> you can see the residues that interact to bind Vitamin D3 and the channel between. Most of these residues are hydrophobic and thus have non polar interactions. Binding of the substrate causes the access channel to close. The B' helix has a flexible C terminus and can adopt a helix or loop conformation, which has van der waal interactions with the F-G loop. The B' helix unwinds outward to allow entrance of the substrate into the active site channel. CYP2R1 has an extended binding site where the access channel is part of the active site.