Ferrochelatase: Difference between revisions
No edit summary |
Michal Harel (talk | contribs) No edit summary |
||
| Line 2: | Line 2: | ||
== Function == | == Function == | ||
'''Ferrochelatase''' (FECH) catalyzes the last step in the formation of heme. FECH adds Fe+2 to protoporphyrin IX converting it to protoheme. The human FECH is a homodimer containing 2 similar domains and an iron-sulfur cluster. | '''Ferrochelatase''' (FECH) catalyzes the last step in the formation of heme. FECH adds Fe+2 to protoporphyrin IX converting it to protoheme. The human FECH is a homodimer containing 2 similar domains and an iron-sulfur cluster. '''Sirohydrochlorin ferrochelatase''' (SirB) catalyzes the addition of Fe+2 to sirohydrochlorin to produce siroheme. | ||
== Disease == | == Disease == | ||
| Line 12: | Line 12: | ||
Ferrochelatase produces <scene name='Journal:JBIC:4/Heme_bound_ferro/5'>heme by insertion of iron into protoporphyrin IX</scene>. It can also <scene name='Journal:JBIC:4/Copper_protorphyrin/4'>insert other metal ions</scene>. However, the ability to insert other <scene name='Journal:JBIC:4/Bound_cu_por/6'>metal ions is species specific</scene>. In this way ''Bacillus subtilis'' ferrochelatase can insert copper into protoporphyrin IX, but to a much less extent cobalt. In contrast, the human and ''Saccharomyces cerevisiae'' ferrochelatases prefer cobalt over copper. <scene name='Journal:JBIC:4/Iron_binding_zoomout/4'>Our structural work</scene> shows that <scene name='Journal:JBIC:4/Iron_binding/9'>one His residue and one Glu residue are direct ligands to the metal ion</scene>, while A third residue, Tyr in ''B. subtilis'', is a third ligand via a water molecule. Human and ''S. cerevisiae'' ferrochelatase utilizes <scene name='Journal:JBIC:4/Iron_bound_met/2'>Met as a third residue to bind the metal ligand.</scene> In the structures of the ferrochelatases the Tyr/Met occupies the same position. We also know that the Tyr residue of the <scene name='Journal:JBIC:4/Bound_cu_por/5'>B. subtilis enzyme</scene> is a <scene name='Journal:JBIC:4/Bound_cu_por/4'>direct ligand to a copper-porphyrin reaction product</scene>. By site directed mutagenesis <scene name='Journal:JBIC:4/Cobalt_bound_met_out/10'>we changed the Tyr to a Met residue</scene> and showed that the metal specificity changed so that the modified ''B. subtilis'' ferrochelatase <scene name='Journal:JBIC:4/Cobalt_bound_met/3'>preferred cobalt over copper</scene>. Two crystal structures are presented. <scene name='Journal:JBIC:4/Iron_binding_zoomout/3'>One shows</scene> how <scene name='Journal:JBIC:4/Iron_binding_zoomout/1'>a metal ion (iron) is coordinated in the active site of the ''B. subtilis'' ferrochelatase</scene>. The <scene name='Journal:JBIC:4/Bound_cu_por/5'>other shows</scene> how a <scene name='Journal:JBIC:4/Bound_cu_por/4'>copper in a reaction product (copper-mesoporphyrin) is coordinated by the Tyr residue</scene> in the ''B. subtilis'' enzyme. | Ferrochelatase produces <scene name='Journal:JBIC:4/Heme_bound_ferro/5'>heme by insertion of iron into protoporphyrin IX</scene>. It can also <scene name='Journal:JBIC:4/Copper_protorphyrin/4'>insert other metal ions</scene>. However, the ability to insert other <scene name='Journal:JBIC:4/Bound_cu_por/6'>metal ions is species specific</scene>. In this way ''Bacillus subtilis'' ferrochelatase can insert copper into protoporphyrin IX, but to a much less extent cobalt. In contrast, the human and ''Saccharomyces cerevisiae'' ferrochelatases prefer cobalt over copper. <scene name='Journal:JBIC:4/Iron_binding_zoomout/4'>Our structural work</scene> shows that <scene name='Journal:JBIC:4/Iron_binding/9'>one His residue and one Glu residue are direct ligands to the metal ion</scene>, while A third residue, Tyr in ''B. subtilis'', is a third ligand via a water molecule. Human and ''S. cerevisiae'' ferrochelatase utilizes <scene name='Journal:JBIC:4/Iron_bound_met/2'>Met as a third residue to bind the metal ligand.</scene> In the structures of the ferrochelatases the Tyr/Met occupies the same position. We also know that the Tyr residue of the <scene name='Journal:JBIC:4/Bound_cu_por/5'>B. subtilis enzyme</scene> is a <scene name='Journal:JBIC:4/Bound_cu_por/4'>direct ligand to a copper-porphyrin reaction product</scene>. By site directed mutagenesis <scene name='Journal:JBIC:4/Cobalt_bound_met_out/10'>we changed the Tyr to a Met residue</scene> and showed that the metal specificity changed so that the modified ''B. subtilis'' ferrochelatase <scene name='Journal:JBIC:4/Cobalt_bound_met/3'>preferred cobalt over copper</scene>. Two crystal structures are presented. <scene name='Journal:JBIC:4/Iron_binding_zoomout/3'>One shows</scene> how <scene name='Journal:JBIC:4/Iron_binding_zoomout/1'>a metal ion (iron) is coordinated in the active site of the ''B. subtilis'' ferrochelatase</scene>. The <scene name='Journal:JBIC:4/Bound_cu_por/5'>other shows</scene> how a <scene name='Journal:JBIC:4/Bound_cu_por/4'>copper in a reaction product (copper-mesoporphyrin) is coordinated by the Tyr residue</scene> in the ''B. subtilis'' enzyme. | ||
==3D structures of ferrochelatase== | |||
[[Ferrochelatase 3D structures]] | |||
</StructureSection> | </StructureSection> | ||
==3D structures of ferrochelatase== | ==3D structures of ferrochelatase== | ||
| Line 49: | Line 52: | ||
**[[2q2n]] – BsFECH + protoporphyrin IX + Mg<br /> | **[[2q2n]] – BsFECH + protoporphyrin IX + Mg<br /> | ||
**[[1c9e]] - BsFECH + N-methylmesoporphyrin + Cu + Mg<br /> | **[[1c9e]] - BsFECH + N-methylmesoporphyrin + Cu + Mg<br /> | ||
* Sirohydrochlorin ferrochelatase | |||
**[[5zt8]] – BsSirB <br /> | |||
**[[5zt7]], [[6jv6]] – BsSirB + Co<br /> | |||
**[[5zt9]] – BsSirB + Ni<br /> | |||
**[[5zta]] – BsSirB + Fe<br /> | |||
}} | }} | ||
== References == | == References == | ||
<references/> | <references/> | ||
[[Category:Topic Page]] | [[Category:Topic Page]] | ||