Abstract

Ferredoxins are ubiquitous proteins with electron transfer activity involved in a variety of biological processes. In this work, we investigated the characteristics and function of Fdx1 from Sorangium cellulosum So ce56 by using a combination of bioinformatics and of biochemical/biophysical approaches. We were able to experimentally confirm a role of Fdx1 in the iron-sulfur cluster biosynthesis by in vitro reduction studies with cluster-loaded So ce56 IscU and by transfer studies of the cluster from the latter protein to apo-aconitase A. Moreover, we found that Fdx1 can replace mammalian adrenodoxin in supporting the activity of bovine CYP11A1. This makes S. cellulosum Fdx1 the first prokaryotic ferredoxin reported to functionally interact with this mammalian enzyme. Although the interaction with CYP11A1 is non-physiological, this is-to the best of our knowledge-the first study to experimentally prove the activity of a postulated ISC-type ferredoxin in both the ISC assembly and a cytochrome P450 system. This proves that a single ferredoxin can be structurally able to provide electrons to both cytochromes P450 and IscU and thus support different biochemical processes. Combining this finding with phylogenetic and evolutionary trace analyses led us to propose the evolution of eukaryotic mitochondrial P450-type ferredoxins and ISC-type ferredoxins from a common prokaryotic ISC-type ancestor.

Links

Publisher Full Text

Authors

Ewen KM, Hannemann F, Iametti S, Morleo A, Bernhardt R

Institution

Department of Biochemistry, Saarland University, D-66041 Saarbrücken, Germany.

Source

Journal of molecular biology 413:5 2011 Nov 11 pg 940-51

MeSH

Aconitate Hydratase
Amino Acid Sequence
Animals
Bacterial Proteins
Cattle
Cholesterol Side-Chain Cleavage Enzyme
Circular Dichroism
Cloning, Molecular
Computational Biology
Evolution, Molecular
Ferredoxins
Iron
Iron-Sulfur Proteins
Mitochondria
Molecular Sequence Data
Myxococcales
NADP
Oxidation-Reduction
Phylogeny
Sequence Homology, Amino Acid
Sulfite Reductase (Ferredoxin)

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21945528