Sandbox Reserved 460: Difference between revisions
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==='''Structure'''=== | ==='''Structure'''=== | ||
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====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. | ||
The protein has a globular fold consisting of 3 alpha/beta domains with the siroheme-iron sulfur cofactor at the interface of the three domains. The siroheme is surrounded by several ionizable amino acid residues that facilitate the binding and subsequent reduction of nitrite. It has 3 iron atoms, one of which is in the siroheme. | The protein has a globular fold consisting of 3 alpha/beta domains with the siroheme-iron sulfur cofactor at the interface of the three domains. The siroheme is surrounded by several ionizable amino acid residues that facilitate the binding and subsequent reduction of nitrite. It has 3 iron atoms, one of which is in the siroheme. | ||
