The D13C variant of Bacillus schlegelii 7Fe ferredoxin is an 8Fe ferredoxin as revealed by 1H-NMR spectroscopy.
The N-terminal cluster binding motif Cys8XXXXXXXCys16....Cys49 of Bacillus schlegelii 7Fe ferredoxin, which provides the ligands to the [Fe3S4]+ cluster, was modified by the mutation Asp13 --> Cys. The mutant D13C is expressed in Escherichia coli as an 8Fe ferredoxin, with NMR properties similar to those of clostridial-type ferredoxins. The full assignment of the hyperfine shifted resonances indicates that Cys13 serves as ligand to the new fourth iron atom in the N-terminal cluster despite the atypical binding sequence CysXXXXCysXXCys....Cys. The C alpha-C beta-S-Fe dihedral angles of all cysteine ligands to the two [Fe4S4]2+ clusters of the D13C variant are similar to those observed in other 8Fe and 4Fe ferredoxins.
Aono
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S
School of Materials Science, Japan Advanced Institute of Science and Technology, Ishikawa.
Bentrop
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D
Bertini
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Luchinat
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C
Macinai
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R
D001224:Aspartic Acid / Q000737:chemistry / Q000235:genetics; D001407:Bacillus / Q000737:chemistry* / Q000235:genetics*; D003545:Cysteine / Q000737:chemistry / Q000235:genetics; D005288:Ferredoxins / Q000737:chemistry* / Q000235:genetics*; D014644:Genetic Variation; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D016297:Mutagenesis, Site-Directed; D015202:Protein Engineering
D005288:Ferredoxins; D008024:Ligands; D001224:Aspartic Acid; D003545:Cysteine