Asp97 is a crucial residue involved in the ligation of the [Fe4S4] cluster of IscA from Acidithiobacillus ferrooxidans.
IscA was proposed to be involved in the iron-sulfur cluster assembly encoded by the iscSUA operon, but the role of IscA in the iron-sulfur cluster assembly still remains controversial. In our previous study, the IscA from A. ferrooxidans was successfully expressed in Escherichia coli, and purified to be a [Fe4S4]-cluster-containing protein. Cys35, Cys99, and Cys101 were important residues in ligating with the [Fe4S4] cluster. In this study, Asp97 was found to be another ligand for the iron-sulfur cluster binding according to site-directed mutagenesis results. Molecular modeling for the IscA also showed that Asp97 was a strong ligand with the [Fe4S4] cluster, which was in good agreement with the experimental results. Thus, the [Fe4S4] cluster in IscA from A. ferrooxidans was ligated by three cysteine residues and one aspartic acid.
Jiang
Huidan
H
Department of Bioengineering, School of Resources Processing and Bioengineering, Central South University, Changsha, P. R. China.
Zhang
Xiaojian
X
Ai
Chenbin
C
Liu
Yuandong
Y
Liu
Jianshe
J
Qiu
Guanzhou
G
Zeng
Jia
J
D042763:Acidithiobacillus / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001216:Asparagine / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010957:Plasmids; D016415:Sequence Alignment; D013455:Sulfur / Q000378:metabolism
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D007506:Iron-Sulfur Proteins; D001216:Asparagine; D013455:Sulfur; D007501:Iron