This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.

Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.


Aconitase

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
(catalytic applet, two scenes)
(→Catalytic mechanism of mitochondrial ACO)
Line 6: Line 6:
== Catalytic mechanism of mitochondrial ACO ==
== Catalytic mechanism of mitochondrial ACO ==
-
<applet load=7acn scene='Aconitase/7acn-sf4/1' size='400' frame='true' align='left' caption="Mitochondrial aconitase from pig, PDB [[7acn]]." />The bulk of citrate cycle processing happens in mitochondria and so, studies concentrated on the mitochondrial ACO. The <scene name='Aconitase/7acn-sf4-3cys/1'>(4Fe-4S) cofactor is held in place</scene> by three sulfur atoms belonging to the cysteins-385, -448, and -451.
+
<applet load=7acn scene='Aconitase/7acn-sf4/1' size='400' frame='true' align='left' caption="Mitochondrial aconitase from pig, PDB [[7acn]]." />The bulk of citrate cycle processing happens in mitochondria and so, studies concentrated on <scene name='Aconitase/7acn-sf4/1'>the mitochondrial ACO</scene>. The <scene name='Aconitase/7acn-sf4-3cys/1'>(4Fe-4S) cofactor is held in place</scene> by three sulfur atoms belonging to the cysteins-385, -448, and -451.
<!--It is clear that, in order to synthesize L-isocitrate, stereoselective catalysis must occur.-->
<!--It is clear that, in order to synthesize L-isocitrate, stereoselective catalysis must occur.-->

Revision as of 16:45, 18 February 2009

Aconitase (ACO) is an enzymatic domain that confers the ability to catalyse the equilibrium

citrate = aconitate + H2O = L-isocitrate

This reaction is part of the citrate (TCA-, Krebs-)cycle.

In most organims, 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.

Catalytic mechanism of mitochondrial ACO

Mitochondrial aconitase from pig, PDB 7acn.

Drag the structure with the mouse to rotate
The bulk of citrate cycle processing happens in mitochondria and so, studies concentrated on . The by three sulfur atoms belonging to the cysteins-385, -448, and -451.


Cytosolic aconitase and its other function

Cytosolic aconitase from rabbit (bound to RNA) and human (with Fe4S4 cluster), from PDB 2ipy and 2b3x.

Drag the structure with the mouse to rotate
A specialty of cAc is that in mammals it has developed a as inhibitor of that carry an . Therefore, the cytosolic cAc is named IREBP for IRE-binding protein when this function is talked about. Only one of the two functions is active, depending on whether is present in the molecule: it's essential for . You can see, by , how much the enzyme structure differs between those two functions.

Weblinks

Retrieved from "http://52.214.119.220/wiki/index.php/Aconitase"
Personal tools