4ISY

Crystal structure of IscS from Mycobacterium tuberculosis

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.59 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.186 
  • R-Value Observed: 0.189 

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Literature

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

Rybniker, J., Pojer, F., Marienhagen, J., Kolly, G.S., Chen, J.M., van Gumpel, E., Hartmann, P., Cole, S.T.

(2014) Biochem J 459: 467-478

  • DOI: 10.1042/BJ20130732
  • Primary Citation of Related Structures:  
    4ISY

  • PubMed Abstract: 

    • 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 ...

    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.

    Organizational Affiliation: 

    *Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.



Macromolecules
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(by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Cysteine desulfuraseA, B, C, D404Mycobacterium tuberculosisMutation(s): 0 
Gene Names: iscS, MT3109, Rv3025c
EC: 2.8.1.7
Find proteins for P9WQ71 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Explore P9WQ71 
Go to UniProtKB:  P9WQ71
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.59 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.186 
  • R-Value Observed: 0.189 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 66.814α = 94.54
b = 78.131β = 104.71
c = 92.774γ = 98.57
Software Package:
Software NamePurpose
XDSdata scaling
PHASERphasing
REFMACrefinement
XDSdata reduction

Structure Validation

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View more in-depth experimental data

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-02-26
    Type: Initial release
  • Version 1.1: 2014-04-23
    Changes: Database references