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  • The cysteine desulfurase IscS of Mycobacterium tuberculosis is involved in iron-sulfur cluster biogenesis and oxidative stress defence.

The cysteine desulfurase IscS of Mycobacterium tuberculosis is involved in iron-sulfur cluster biogenesis and oxidative stress defence.

The Biochemical journal (2014-02-20)
Jan Rybniker, Florence Pojer, Jan Marienhagen, Gaëlle S Kolly, Jeffrey M Chen, Edeltraud van Gumpel, Pia Hartmann, Stewart T Cole
RESUMEN

The complex multiprotein systems for the assembly of protein-bound iron-sulfur (Fe-S) clusters are well defined in Gram-negative model organisms. However, little is known about Fe-S cluster biogenesis in other bacterial species. The ISC (iron-sulfur cluster) operon of Mycobacterium tuberculosis lacks several genes known to be essential for the function of this system in other organisms. However, the cysteine desulfurase IscSMtb (Rv number Rv3025c; Mtb denotes M. tuberculosis) is conserved in this important pathogen. The present study demonstrates that deleting iscSMtb renders the cells microaerophilic and hypersensitive to oxidative stress. Moreover, the ∆iscSMtb mutant shows impaired Fe-S cluster-dependent enzyme activity, clearly indicating that IscSMtb is associated with Fe-S cluster assembly. An extensive interaction network of IscSMtb with Fe-S proteins was identified, suggesting a novel mechanism of sulfur transfer by direct interaction with apoproteins. Interestingly, the highly homologous IscS of Escherichia coli failed to complement the ∆iscSMtb mutant and showed a less diverse protein-interaction profile. To identify a structural basis for these observations we determined the crystal structure of IscSMtb, which mirrors adaptations made in response to an ISC operon devoid of IscU-like Fe-S cluster scaffold proteins. We conclude that in M. tuberculosis IscS has been redesigned during evolution to compensate for the deletion of large parts of the ISC operon.

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Sigma-Aldrich
L-cisteína, from non-animal source, BioReagent, suitable for cell culture, ≥98%
Sigma-Aldrich
L-cisteína, 97%
Sigma-Aldrich
L-cisteína, BioUltra, ≥98.5% (RT)
SAFC
L-cisteína
Sigma-Aldrich
L-cisteína, ≥97%, FG
Supelco
L-cisteína, certified reference material, TraceCERT®, Manufactured by: Sigma-Aldrich Production GmbH, Switzerland
Sigma-Aldrich
L-cisteína, Wacker Chemie AG, ≥98.0%