Biogenesis of Fe-S cluster by the bacterial Suf system: SufS and SufE form a new type of cysteine desulfurase.
Biosynthesis of iron-sulfur clusters (Fe-S) depends on multiprotein systems. Recently, we described the SUF system of Escherichia coli and Erwinia chrysanthemi as being important for Fe-S biogenesis under stressful conditions. The SUF system is made of six proteins: SufC is an atypical cytoplasmic ABC-ATPase, which forms a complex with SufB and SufD; SufA plays the role of a scaffold protein for assembly of iron-sulfur clusters and delivery to target proteins; SufS is a cysteine desulfurase which mobilizes the sulfur atom from cysteine and provides it to the cluster; SufE has no associated function yet. Here we demonstrate that: (i) SufE and SufS are both cystosolic as all members of the SUF system; (ii) SufE is a homodimeric protein; (iii) SufE forms a complex with SufS as shown by the yeast two-hybrid system and by affinity chromatography; (iv) binding of SufE to SufS is responsible for a 50-fold stimulation of the cysteine desulfurase activity of SufS. This is the first example of a two-component cysteine desulfurase enzyme.
Loiseau
Laurent
L
LCB-CNRS, IBSM, 31 Chemin Joseph Aiguier, 13402 Marseille 20, France.
Ollagnier-de-Choudens
Sandrine
S
Nachin
Laurence
L
Fontecave
Marc
M
Barras
Frédéric
F
D000409:Alanine / Q000737:chemistry; D001426:Bacterial Proteins / Q000502:physiology*; D013437:Carbon-Sulfur Lyases; D002845:Chromatography; D002850:Chromatography, Gel; D003545:Cysteine / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D016974:Dickeya chrysanthemi / Q000378:metabolism; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D015151:Immunoblotting; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000502:physiology*; D007700:Kinetics; D008190:Lyases / Q000737:chemistry* / Q000502:physiology*; D008954:Models, Biological; D008956:Models, Chemical; D016297:Mutagenesis, Site-Directed; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017279:Selenocysteine / Q000494:pharmacology; D013347:Subcellular Fractions; D013997:Time Factors; D020798:Two-Hybrid System Techniques
D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D017279:Selenocysteine; D008190:Lyases; D013437:Carbon-Sulfur Lyases; C080546:cysteine desulfurase; D003545:Cysteine; D000409:Alanine