Shepherd, Mark and Dailey, T.A. and Dailey, H.A. (2006) A new class of [2Fe-2S]-cluster-containing protoporphyrin (IX) ferrochelatases. The Biochemical journal, 397 (1). pp. 47-52. ISSN 1470-8728. (The full text of this publication is not available from this repository)
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Protoporphyrin (IX) ferrochelatase catalyses the insertion of ferrous iron into protoporphyrin IX to form haem. These ferrochelatases exist as monomers and dimers, both with and without [2Fe-2S] clusters. The motifs for [2Fe-2S] cluster co-ordination are varied, but in all cases previously reported, three of the four cysteine ligands are present in the 30 C-terminal residues and the fourth ligand is internal. In the present study, we demonstrate that a group of micro-organisms exist which possess protoporphyrin (IX) ferrochelatases containing [2Fe-2S] clusters that are co-ordinated by a group of four cysteine residues contained in an internal amino acid segment of approx. 20 residues in length. This suggests that these ferrochelatases have evolved along a different lineage than other bacterial protoporphyrin (IX) ferrochelatases. For example, Myxococcus xanthus protoporphyrin (IX) ferrochelatase ligates a [2Fe-2S] cluster via cysteine residues present in an internal segment. Site-directed mutagenesis of this ferrochelatase demonstrates that changing one cysteine ligand into serine results in loss of the cluster, but unlike eukaryotic protoporphyrin (IX) ferrochelatases, this enzyme retains its activity. These data support a role for the [2Fe-2S] cluster in iron affinity, and strongly suggest convergent evolution of this feature in prokaryotes.
|Divisions:||Faculties > Science Technology and Medical Studies > School of Biosciences|
|Depositing User:||Mark Shepherd|
|Date Deposited:||01 Sep 2011 16:00|
|Last Modified:||25 Apr 2012 08:49|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/28097 (The current URI for this page, for reference purposes)|