Sandbox Reserved 460: Difference between revisions
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The electron flow proceeds initially from reduced ferredoxin to the enzyme's [4Fe–4S] cluster and subsequently from the reduced cluster to the siroheme. Since ferredoxin is a one-electron donor, the enzyme must accumulate six electrons in one-electron steps before it can reduce nitrite. | The electron flow proceeds initially from reduced ferredoxin to the enzyme's [4Fe–4S] cluster and subsequently from the reduced cluster to the siroheme. Since ferredoxin is a one-electron donor, the enzyme must accumulate six electrons in one-electron steps before it can reduce nitrite. | ||
[[Image:Pathway.jpeg]] | [[Image:Pathway.jpeg]] | ||
==='''Structure'''=== | ==='''Structure'''=== | ||
---- | ---- | ||
====Secondary Structures==== | |||
Nitrite Reductase has only one chain consisting of 591 residues. There are 33 <scene name='Sandbox_Reserved_460/Helices/1'>helices</scene> (33% of chain) and 33 <scene name='Sandbox_Reserved_460/Beta_sheets/1'>beta strands</scene> (21% of chain). | |||
====Ligands==== | ====Ligands==== | ||
Siroheme is an iron-containing isobacteriochlorin, a modified tetrapyrrole similar in structure to both heme and chlorophyll. It is a heme-like prosthetic group used by nitrite reductase to carry out the six-electron reduction of nitrogen. Nitrite is reduced to ammonium while still bound to siroheme. | Siroheme is an iron-containing isobacteriochlorin, a modified tetrapyrrole similar in structure to both heme and chlorophyll. It is a heme-like prosthetic group used by nitrite reductase to carry out the six-electron reduction of nitrogen. Nitrite is reduced to ammonium while still bound to siroheme. | ||
