Aconitase: Difference between revisions
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'''Aconitase (ACO)''' is an enzymatic domain that confers the ability to catalyse the equilibrium | |||
:citrate = aconitate + H<sub>2</sub>O = 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 metazoa and up, a second copy was forked in mitochondria (mAc). A specialty of cAc is that in mammals it has developed a second function as inhibitor of those mRNA that carry an iron-regulatory element (IRE). 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 the (4Fe4S) cofactor is present in the molecule: it's essential for the ACO function. | |||
== Available structures == | |||
In the PDB, nearly all deposited structures are from mammals, [[1l5j]] is from ''E.coli''. Also, only [[2ipy]] shows the IREBP function of cAc---it's also the only from rabbit. There are only two other cAc structures, with and without citrate, also the only from human. All other structures are either cow or pig, and a mutant from pig; all three proteins with several different ligands and inhibitors. | |||
*[[1aco]] - mAc (''Bos taurus'') with ''trans''-aconitate (inhibitor) | *[[1aco]] - mAc (''Bos taurus'') with ''trans''-aconitate (inhibitor) | ||
*[[1ami]] - mAc (''Bos taurus'') with methylisocitrate | *[[1ami]] - mAc (''Bos taurus'') with methylisocitrate | ||