Home | Contact

Aconitase (aconitate hydratase) (EC 4.2.1.3) [1] is the enzyme from the tricarboxylic acid cycle that catalyzes the reversible isomerization of citrate and isocitrate. Cis-aconitate is formed as an intermediary product during the course of the reaction. In eukaryotes two isozymes of aconitase are known to exist: one found in the mitochondrial matrix and the other found in the cytoplasm. Aconitase, in its active form, contains a 4Fe-4S iron-sulfur cluster; three cysteine residues have been shown to be ligands of the 4Fe-4S cluster.

It has been shown that the aconitase family also contains the following proteins:

• Iron-responsive element binding protein (IRE-BP). IRE-BP is a cytosolic protein that binds to iron-responsive elements (IREs). IREs are stem-loop structures found in the 5'UTR of ferritin, and delta aminolevulinic acid synthase mRNAs, and in the 3'UTR of transferrin receptor mRNA. IRE-BP also express aconitase activity.
• 3-isopropylmalate dehydratase (EC 4.2.1.33) (isopropylmalate isomerase), the enzyme that catalyzes the second step in the biosynthesis of leucine.
• Homoaconitase (EC 4.2.1.36) (homoaconitate hydratase), an enzyme that participates in the α-aminoadipate pathway of lysine biosynthesis and that converts cis-homoaconitate into homoisocitric acid.
• Esherichia coli protein ybhJ.

As a signature for proteins from the aconitase family we have selected two conserved regions that contain the three cysteine ligands of the 4Fe-4S cluster.

December 2004 / Pattern and text revised.

PROSITE methods (with tools and information) covered by this documentation:

ACONITASE_1, PS00450; Aconitase family signature 1  (PATTERN)

Consensus pattern: [LIVM]-x(2)-[GSACIVM]-x-[LIV]-[GTIV]-[STP]-C-x(0,1)-T-N-[GSTANI]-x(4)-[LIVMA] C binds the iron-sulfur center Sequences known to belong to this class detected by the pattern: ALL, except for ybhJ Other sequence(s) detected in Swiss-Prot: NONE.

• Retrieve an alignment of Swiss-Prot true positive hits:   Clustal format, color, condensed view  / Clustal format, color  / Clustal format, plain text  / Fasta format • Retrieve the sequence logo from the alignment • Taxonomic tree view of all Swiss-Prot/TrEMBL entries matching PS00450 • Retrieve a list of all Swiss-Prot/TrEMBL entries matching PS00450 • Scan Swiss-Prot/TrEMBL entries against PS00450 • view ligand binding statistics

Matching PDB structures: 1ACO 1AMI 1AMJ 1B0J ... [ALL]

ACONITASE_2, PS01244; Aconitase family signature 2  (PATTERN)

Consensus pattern: G-x(2)-[LIVWPQT]-x(3)-[GACST]-C-[GSTAM]-[LIMPTA]-C-[LIMV]-[GA] The 2 C's bind the iron-sulfur center Sequences known to belong to this class detected by the pattern: ALL, except for ybhJ Other sequence(s) detected in Swiss-Prot: NONE.

• Retrieve an alignment of Swiss-Prot true positive hits:   Clustal format, color, condensed view  / Clustal format, color  / Clustal format, plain text  / Fasta format • Retrieve the sequence logo from the alignment • Taxonomic tree view of all Swiss-Prot/TrEMBL entries matching PS01244 • Retrieve a list of all Swiss-Prot/TrEMBL entries matching PS01244 • Scan Swiss-Prot/TrEMBL entries against PS01244 • view ligand binding statistics

Matching PDB structures: 1ACO 1AMI 1AMJ 1B0J ... [ALL]

1	Authors	Gruer M.J., Artymiuk P.J., Guest J.R.
	Title	The aconitase family: three structural variations on a common theme.
	Source	Trends Biochem. Sci. 22:3-6(1997).
	PubMed ID	9020582

PROSITE is copyright. It is produced by the SIB Swiss Institute Bioinformatics. There are no restrictions on its use by non-profit institutions as long as its content is in no way modified. Usage by and for commercial entities requires a license agreement. For information about the licensing scheme send an email to

Prosite License or see: prosite_license.html.


View entry in original PROSITE document format
View entry in raw text format (no links)

SIB Swiss Institute of Bioinformatics | Disclaimer