Functional roles of the aromatic residues in the stabilization of the [Fe(4)S(4)] cluster in the Iro protein from Acidithiobacillus ferrooxidans.
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.
Zeng
Jia
J
Center for Biomedical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha, Hunan 410082, P. R. China. zengjcsu@yahoo.com.cn
Liu
Qing
Q
Zhang
Xiaojian
X
Mo
Hongyu
H
Wang
Yiping
Y
Chen
Qian
Q
Liu
Yuandong
Y
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
D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D010088:Oxidoreductases; C074859:iron oxidase, Thiobacillus ferrooxidans