Faculty Opinions recommendation of Biotin synthase is a pyridoxal phosphate-dependent cysteine desulfurase.

ABSTRACT Many eubacteria are resistant to the toxic oxidizing agent potassium tellurite, and tellurite resistance involves diverse biochemical mechanisms. Expression of the iscS gene from Geobacillus stearothermophilus V, which is naturally resistant to tellurite, confers tellurite resistance in Escherichia coli K-12, which is naturally sensitive to tellurite. The G. stearothermophilus iscS gene encodes a cysteine desulfurase. A site-directed mutation in iscS that prevents binding of its pyridoxal phosphate cofactor abolishes both enzyme activity and its ability to confer tellurite resistance in E. coli. Expression of the G. stearothermophilus iscS gene confers tellurite resistance in tellurite-hypersensitive E. coli iscS and sodA sodB mutants (deficient in superoxide dismutase) and complements the auxotrophic requirement of an E. coli iscS mutant for thiamine but not for nicotinic acid. These and other results support the hypothesis that the reduction of tellurite generates superoxide anions and that the primary targets of superoxide damage in E. coli are enzymes with iron-sulfur clusters.

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Contribution of Cysteine Desulfurase (NifS Protein) to the Biotin Synthase Reaction of Escherichia coli

Journal of Bacteriology ◽

10.1128/jb.182.10.2879-2885.2000 ◽

2000 ◽

Vol 182 (10) ◽

pp. 2879-2885 ◽

Cited By ~ 25

Author(s):

Tatsuya Kiyasu ◽

Akira Asakura ◽

Yoshie Nagahashi ◽

Tatsuo Hoshino

Keyword(s):

Escherichia Coli ◽

Reaction System ◽

Cysteine Desulfurase ◽

Biotin Synthase ◽

Iron Sulfur Cluster ◽

Free System ◽

E Coli ◽

Iron Sulfur

ABSTRACT The contribution of cysteine desulfurase, the NifS protein ofKlebsiella pneumoniae and the IscS protein ofEscherichia coli, to the biotin synthase reaction was investigated in in vitro and in vivo reaction systems with E. coli. When the nifS and nifU genes ofK. pneumoniae were coexpressed in E. coli, NifS and NifU proteins in complex (NifU/S complex) and NifU monomer forms were observed. Both the NifU/S complex and the NifU monomer stimulated the biotin synthase reaction in the presence of l-cysteine in an in vitro reaction system. The NifU/S complex enhanced the production of biotin from dethiobiotin by the cells growing in an in vivo reaction system. Moreover, the IscS protein of E. colistimulated the biotin synthase reaction in the presence ofl-cysteine in the cell-free system. These results strongly suggest that cysteine desulfurase participates in the biotin synthase reaction, probably by supplying sulfur to the iron-sulfur cluster of biotin synthase.

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Sulfur Mobilization for Fe-S Cluster Assembly by the Essential SUF Pathway in the Plasmodium falciparum Apicoplast and Its Inhibition

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02711-13 ◽

2014 ◽

Vol 58 (6) ◽

pp. 3389-3398 ◽

Cited By ~ 20

Author(s):

Manish Charan ◽

Nidhi Singh ◽

Bijay Kumar ◽

Kumkum Srivastava ◽

Mohammad Imran Siddiqi ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Pyridoxal Phosphate ◽

Inhibitory Concentration ◽

Cluster Assembly ◽

Cysteine Desulfurase ◽

Content Type ◽

Biochemical Investigation ◽

Parasite Survival

ABSTRACTThe plastid of the malaria parasite, the apicoplast, is essential for parasite survival. It houses several pathways of bacterial origin that are considered attractive sites for drug intervention. Among these is the sulfur mobilization (SUF) pathway of Fe-S cluster biogenesis. Although the SUF pathway is essential for apicoplast maintenance and parasite survival, there has been limited biochemical investigation of its components and inhibitors ofPlasmodiumSUFs have not been identified. We report the characterization of two proteins,Plasmodium falciparumSufS (PfSufS) andPfSufE, that mobilize sulfur in the first step of Fe-S cluster assembly and confirm their exclusive localization to the apicoplast. The cysteine desulfurase activity ofPfSufS is greatly enhanced byPfSufE, and thePfSufS-PfSufE complex is detectedin vivo. Structural modeling of the complex reveals proximal positioning of conserved cysteine residues of the two proteins that would allow sulfide transfer from the PLP (pyridoxal phosphate) cofactor-bound active site ofPfSufS. Sulfide release from thel-cysteine substrate catalyzed byPfSufS is inhibited by the PLP inhibitord-cycloserine, which forms an adduct withPfSufS-bound PLP.d-Cycloserine is also inimical to parasite growth, with a 50% inhibitory concentration close to that reported forMycobacterium tuberculosis, against which the drug is in clinical use. Our results establish the function of two proteins that mediate sulfur mobilization, the first step in the apicoplast SUF pathway, and provide a rationale for drug design based on inactivation of the PLP cofactor ofPfSufS.

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