title: The IscA from Acidithiobacillus ferrooxidans is an iron-sulfur protein which assemble the [Fe4S4] cluster with intracellular iron and sulfur.
abstract: IscA was proposed to be involved in the iron-sulfur cluster assembly in Acidithiobacillus ferrooxidans encoded by the iscSUA operon, but the role of IscA in the iron-sulfur cluster assembly still remains controversial. In this study, the IscA from A. ferrooxidans ATCC 23270 was successfully expressed in Escherichia coli, and purified by affinity chromatography to homogeneity. To our surprise, the purified IscA was observed to be an iron-sulfur protein according to MALDI-TOF-MS and spectra results, which was capable of recruiting intracellular iron and sulfur and hosted a stable [Fe4S4] cluster. Site-directed mutagenesis for the protein revealed that Cys35, Cys99 and Cys101 were in ligating with the [Fe4S4] cluster. The [Fe4S4] cluster could be assembled in apoIscA with Fe2+ and sulfide in vitro. The IscA from A. ferrooxidans may function as a scaffold protein for the pre-assembly of Fe-S cluster and then transfer it to target proteins in A. ferrooxidans.
authors.affiliation: Department of Bioengineering, School of Resources Processing and Bioengineering, Central South University, Changsha 410083, PR China.
authors.forename: Jia
authors.initials: J
authors.lastname: Zeng
authors.forename: Meimei
authors.initials: M
authors.lastname: Geng
authors.forename: Huidan
authors.initials: H
authors.lastname: Jiang
authors.forename: Yuandong
authors.initials: Y
authors.lastname: Liu
authors.forename: Jianshe
authors.initials: J
authors.lastname: Liu
authors.forename: Guanzhou
authors.initials: G
authors.lastname: Qiu
mesh_terms: D042763:Acidithiobacillus / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D003545:Cysteine / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D007501:Iron / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D016415:Sequence Alignment; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013056:Spectrophotometry, Ultraviolet; D013455:Sulfur / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D013455:Sulfur; D007501:Iron; D003545:Cysteine