title: Functional roles of the aromatic residues in the stabilization of the [Fe(4)S(4)] cluster in the Iro protein from Acidithiobacillus ferrooxidans.
abstract: The Iro protein is a member of HiPIP family with the [Fe(4)S(4)] cluster for electron transfer. Many reports proposed that the conserved aromatic residues might be responsible for the stability of the iron-sulfur cluster in HiPIP. In this study, Tyr10 was found to be a critical residue for the stability of the [Fe(4)S(4)] cluster according to site-directed mutagenesis results. Tyr10, Phe26 and Phe48 were essential for the stability of the [Fe(4)S(4)] cluster under acidic condition. Trp44 were not involved in the stability of the [Fe(4)S(4)] cluster. Molecular structure modeling for the mutant Tyr10 proteins revealed that the aromatic group of Tyr10 may form a hydrophobic barrier to protect the [Fe(4)S(4)] cluster from solvent.
authors.affiliation: Center for Biomedical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha, Hunan 410082, P. R. China. zengjcsu@yahoo.com.cn
authors.forename: Jia
authors.initials: J
authors.lastname: Zeng
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Zhang
authors.forename: Hongyu
authors.initials: H
authors.lastname: Mo
authors.forename: Yiping
authors.initials: Y
authors.lastname: Wang
authors.forename: Qian
authors.initials: Q
authors.lastname: Chen
authors.forename: Yuandong
authors.initials: Y
authors.lastname: Liu
mesh_terms: D042763:Acidithiobacillus / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D055550:Protein Stability; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D010088:Oxidoreductases; C074859:iron oxidase, Thiobacillus ferrooxidans