Nitric Oxide Synthase: Difference between revisions
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===H<sub>4</sub>B=== | ===H<sub>4</sub>B=== | ||
[[image:bh4.png| | [[image:bh4.png|left|frame|Structure of tetrahydrobiopterin]] | ||
<applet load='2g6h' size='300' frame='true' align='right' caption='Insert caption here' /> | <applet load='2g6h' size='300' frame='true' align='right' caption='Insert caption here' /> | ||
<scene name='Sandbox_5/Nos_oxygenase_bh4/11'>H4B</scene> is a cofactor. NOS contains two molecules of <scene name='Sandbox_5/Begge_h4b/1'>H4B</scene>, one in each monomer. The active center forms a kind of tunnel, because of the dimeric structure. This gives H<sub>4</sub>B the opportunity to play a big role in the control of subunit interactions and active-center formation. H<sub>4</sub>B therefor is more of a structurel cofactor, in that it keeps the dimer stabilized by integration in to the hydrophobic parts of the dimer. Here it helps substrate interactions by lining the active-center channel and hydrogen bonding to the heme propionate amd to alfa7 which is two elements involved in L-Arg binding. So H<sub>4</sub>B is not the molecule that hydroxylates the substrate (L-Arg) nor activating the hemebound oxygen. | <scene name='Sandbox_5/Nos_oxygenase_bh4/11'>H4B</scene> is a cofactor. NOS contains two molecules of <scene name='Sandbox_5/Begge_h4b/1'>H4B</scene>, one in each monomer. The active center forms a kind of tunnel, because of the dimeric structure. This gives H<sub>4</sub>B the opportunity to play a big role in the control of subunit interactions and active-center formation. H<sub>4</sub>B therefor is more of a structurel cofactor, in that it keeps the dimer stabilized by integration in to the hydrophobic parts of the dimer. Here it helps substrate interactions by lining the active-center channel and hydrogen bonding to the heme propionate amd to alfa7 which is two elements involved in L-Arg binding. So H<sub>4</sub>B is not the molecule that hydroxylates the substrate (L-Arg) nor activating the hemebound oxygen. | ||