The sources of inorganic sulfur in the process of cluster protein Fnr[4Fe-4S2+ reconstruction in Escherichia coli cells cultivated with NO-donating agents

• Published in: Biofizika Vol. 57; no. 2; p. 247
• Main Authors: Vasil'eva, S V, Strel'tsova, D A, Vlaskina, A V, Mikoian, V D, Vanin, A F
• Format: Journal Article
• Language: Russian
• Published: Russia (Federation) 01-03-2012
• Subjects: Electron Spin Resonance Spectroscopy; Escherichia coli - growth & development; Escherichia coli - metabolism; Escherichia coli Proteins - biosynthesis; Escherichia coli Proteins - metabolism; Gene Expression Regulation, Bacterial - drug effects; Gene Expression Regulation, Bacterial - physiology; Iron - metabolism; Iron-Sulfur Proteins - metabolism; Nitric Oxide Donors - pharmacology; Nitrogen Oxides - metabolism; Sulfides - metabolism; Sulfides - pharmacology; Sulfur - metabolism; Sulfur - pharmacology
• ISSN: 0006-3029

Dinitrosyl iron complexes (DNICs) with thiol ligands--binuclear and mononuclear--inhibited aidB gene expression in E. coli cells. This process is due to the nitrosylation of the active center in iron-sulfur protein Fnr [4Fe-4S]2+ by low-molecular DNICs. The next step is transformation of the above DNICs into the DNICs with the thiol groups in the apo-form of Fnr protein. These nitrosylated proteins are characterized by the EPR signal with g perpendicular = 2.04 and g parallel 1 = 2,014. An addition of sulfur containing L-Cys or N-A-L-Cys as well as Na2S to the cells lead to the increasing in the aidB gene expression simultaneously with an appearance of the EPR signal with g perpendicular = 2.04 and g parallel = 2.02 as the characteristics of the DNICs with persulfide (R-S-S-) ligands. We suppose that the recovery of the aidB gene activity was due to the accumulation of inorganic sulfur in the cells and reconstruction of the active center in Fnr[4Fe-4S]2+. It appears that the above process is the function of L-cysteine-desulfurase protein which repaired the active center of Fnr[4Fe-4S]2+ protein using the sulfur from L-Cys or N-A-L-Cys after its deacetylation. On the other side the ions of inorganic sulfur being reacted with SH-groups led to the transformation of DNIC with thiol ligands into the persulfides. Na2S was the most potent activator of the aidB gene expression in our experiments.