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The D13C variant of Bacillus schlegelii 7Fe ferredoxin is an 8Fe ferredoxin as revealed by 1 H‐NMR spectroscopy
Author(s) -
Aono Shigetoshi,
Bentrop Detlef,
Bertini Ivano,
Luchinat Claudio,
Macinai Riccardo
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00834-x
Subject(s) - ferredoxin , chemistry , crystallography , nuclear magnetic resonance spectroscopy , cysteine , stereochemistry , ligand (biochemistry) , iron–sulfur cluster , biochemistry , enzyme , receptor
The N‐terminal cluster binding motif Cys 8 Cys 16 ....Cys 49 of Bacillus schlegelii 7Fe ferredoxin, which provides the ligands to the [Fe 3 S 4 ] + cluster, was modified by the mutation Asp 13 →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 Cys 13 serves as ligand to the new fourth iron atom in the N‐terminal cluster despite the atypical binding sequence CysXXXXCysXXCys....Cys. The Cα–Cβ–S–Fe dihedral angles of all cysteine ligands to the two [Fe 4 S 4 ] 2+ clusters of the D13C variant are similar to those observed in other 8Fe and 4Fe ferredoxins.