Publications

• Cysteine desulfurase activity indicates a role for NIFS in metallocluster biosynthesis.

  Zheng L., White R.H., Cash V.L., Jack R.F., Dean D.R.

  Biological nitrogen fixation is catalyzed by nitrogenase, a complex metalloenzyme composed of two separately purifiable component proteins encoded by the structural genes nifH, nifD, and nifK. Deletion of the Azotobacter vinelandii nifS gene lowers the activities of both nitrogenase component prot ... >> More

  Biological nitrogen fixation is catalyzed by nitrogenase, a complex metalloenzyme composed of two separately purifiable component proteins encoded by the structural genes nifH, nifD, and nifK. Deletion of the Azotobacter vinelandii nifS gene lowers the activities of both nitrogenase component proteins. Because both nitrogenase component proteins have metallocluster prosthetic groups that are composed of iron- and sulfur-containing cores, this result indicated that the nifS gene product could be involved in the mobilization of the iron or sulfur required for metallocluster formation. In the present work, it is shown that NIFS is a pyridoxal phosphate-containing homodimer that catalyzes the formation of L-alanine and elemental sulfur by using L-cysteine as substrate. NIFS activity is extremely sensitive to thiol-specific alkylating reagents, which indicates the participation of a cysteinyl thiolate at the active site. Based on these results we propose that an enzyme-bound cysteinyl persulfide that requires the release of the sulfur from the substrate L-cysteine for its formation ultimately provides the inorganic sulfide required for nitrogenase metallocluster formation. The recent discovery of nifS-like genes in non-nitrogen-fixing organisms also raises the possibility that the reaction catalyzed by NIFS represents a universal mechanism that involves pyridoxal phosphate chemistry, in the mobilization of the sulfur required for metallocluster formation. << Less

  Proc. Natl. Acad. Sci. U.S.A. 90:2754-2758(1993) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Bacterial cysteine desulfurases: their function and mechanisms.

  Mihara H., Esaki N.

  Cysteine desulfurase is a pyridoxal 5'-phosphate (PLP)-dependent homodimeric enzyme that catalyzes the conversion of L-cysteine to L-alanine and sulfane sulfur via the formation of a protein-bound cysteine persulfide intermediate on a conserved cysteine residue. Increased evidence for the function ... >> More

  Cysteine desulfurase is a pyridoxal 5'-phosphate (PLP)-dependent homodimeric enzyme that catalyzes the conversion of L-cysteine to L-alanine and sulfane sulfur via the formation of a protein-bound cysteine persulfide intermediate on a conserved cysteine residue. Increased evidence for the functions of cysteine desulfurases has revealed their important roles in the biosyntheses of Fe-S clusters, thiamine, thionucleosides in tRNA, biotin, lipoic acid, molybdopterin, and NAD. The enzymes are also proposed to be involved in cellular iron homeostasis and in the biosynthesis of selenoproteins. The mechanisms for sulfur mobilization mediated by cysteine desulfurases are as yet unknown, but enzymes capable of providing a variety of biosynthetic pathways for sulfur/selenium-containing biomolecules are probably applicable to the production of cofactors and the bioconversion of useful compounds. << Less

  Appl Microbiol Biotechnol 60:12-23(2002) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Formation of iron-sulfur clusters in bacteria: an emerging field in bioinorganic chemistry.

  Frazzon J., Dean D.R.

  Biological iron-sulfur clusters are chemically versatile inorganic structures that are attached to many proteins. These clusters are intimately involved in the functions of their partner proteins and they are required to sustain life on earth. Recent work has demonstrated that, in spite of their s ... >> More

  Biological iron-sulfur clusters are chemically versatile inorganic structures that are attached to many proteins. These clusters are intimately involved in the functions of their partner proteins and they are required to sustain life on earth. Recent work has demonstrated that, in spite of their simple structures, the assembly and insertion of iron-sulfur clusters into their protein partners is a complex biological process. This complexity is probably related to the cellular toxicity of iron and sulfur in their free forms. << Less

  Curr Opin Chem Biol 7:166-173(2003) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.