Syntheses of 2Fe–2S Ferredoxin Model Complexes of Cys-Containing Oligopeptides by Reaction with Fe2S22+ Ion or by Sulfide Incorporation

Abstract

The 2Fe–2S ferredoxin model complexes of two peptide ligands, Z–l-Ala–l-Cys–OMe (Z=benzyloxycarbonyl) and Z–l-Cys–l-Ala–l-Ala–l-Cys–OMe, were synthesized from [NMe4]2[Fe2S2Cl4] by addition of triethylamine. These were characterized by absorption, CD, and MCD spectra in dimethyl sulfoxide or N,N-dimethylformamide. Incorporation of inorganic sulfide to the iron(III) complex, [Fe(Z–cys–Ala–Ala–cys–OMe)2]− (rubredoxin models), results in the selective formation of a 2Fe–2S cluster by a controlling ability of the peptides.