Aconitase: Difference between revisions
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:citrate = aconitate + H<sub>2</sub>O = L-isocitrate | :citrate = aconitate + H<sub>2</sub>O = L-isocitrate | ||
This reaction is part of the citrate (TCA-, Krebs-)cycle. | This reaction is part of the citrate (TCA-, Krebs-)cycle. | ||
The images at the left and at the right correspond to one representative Aconitase, ''i.e.'' the crystal structure of Bovine Aconitase ([[1amj]]). | |||
In most | In most organisms, there is a cytosolic enzyme with an ACO domain (cAc), and in eukaryotes, a second copy of it was introduced with mitochondria (mAc). Plants developed even more copies in mitochondria. | ||
Aconitase contains a Fe4S4 cluster which converts to Fe3S4 when the enzyme is inactive. In humans, two types of ACO are expressed: the soluble ACO1 and the mitochondrial ACO2. | |||
Aconitase (PDB [[7acn]]) is a single polypeptide (M<sub>r</sub> 83kD) that catalyzes the reversible isomerization of citrate and isocitrate.<ref name="Zheng">Zheng, L., Kennedy, MC., Beinert, H., Zalkin, H. "Mutational analysis of active site residues in pig heart aconitase." J Biol Chem 1992, 267, 7895-7903.</ref> It is the second enzyme in the Citric acid cycle, which is a series of enzyme-catalysed chemical reactions that is crucial to aerobic cellular respiration and the production of ATP. | Aconitase from pig (PDB [[7acn]]) is a single polypeptide (M<sub>r</sub> 83kD) that catalyzes the reversible isomerization of citrate and isocitrate.<ref name="Zheng">Zheng, L., Kennedy, MC., Beinert, H., Zalkin, H. "Mutational analysis of active site residues in pig heart aconitase." J Biol Chem 1992, 267, 7895-7903.</ref> It is the second enzyme in the Citric acid cycle, which is a series of enzyme-catalysed chemical reactions that is crucial to aerobic cellular respiration and the production of ATP. | ||
==Structure== | ==Structure== | ||
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Along with serving as a catalyst, aconitase is a member of the iron regulatory protien-1 (IRP-1) family. These enzymes have been found to play a role in regulatory RNA-binding proteins. This suggests a novel role for Fe-S clusters as post-translational regulatory switches.<ref name="Frishman" /> | Along with serving as a catalyst, aconitase is a member of the iron regulatory protien-1 (IRP-1) family. These enzymes have been found to play a role in regulatory RNA-binding proteins. This suggests a novel role for Fe-S clusters as post-translational regulatory switches.<ref name="Frishman" /> | ||
== Available 3D structures of Aconitase== | |||
=== ACO === | |||
[[1b0k]] – pACO (mutant) – pig<br /> | |||
[[5acn]] – pACO+Fe3S4<br /> | |||
[[6acn]] - pACO+Fe4S4<br /> | |||
[[1amj]], [[1nit]] – cACO - cow<br /> | |||
=== ACO+citrate === | |||
[[1c96]] - pACO (mutant)+citrate<br /> | |||
[[1b0m]] - pACO (mutant)+fluorocitrate<br /> | |||
=== ACO+aconitate === | |||
[[1fgh]] – cACO+4-hydroxy-aconitate <br /> | |||
[[1aco]] – cACO+transaconitate<br /> | |||
[[1nis]] - cACO+transaconitate+nitrocitrate<br /> | |||
=== ACO+isocitrate === | |||
[[7acn]] - pACO +isocitrate<br /> | |||
[[1c97]], [[1b0j]] - pACO (mutant)+isocitrate<br /> | |||
[[1ami]], [[8acn]] – cACO+isocitrate<br /> | |||
=== ACO1 === | |||
[[2b3x]], [[2b3y]] – hACO1 – human<br /> | |||
[[2ipy]] – rACO1 (mutant)+ferritin H IRE-RNA – rabbit<br /> | |||
=== ACO2 === | |||
[[1l5j]] – ACO2 – ''Escherichia coli''<br /> | |||
<!--== Available structures == | <!--== Available structures == | ||
