Biological Assembly 1  

 3D View: Structure | 1D-3D View | Electron Density | Validation Report | Ligand Interaction

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Biological Assembly 2  

 3D View: Structure | 1D-3D View | Electron Density | Validation Report | Ligand Interaction

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 2 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 170.82 kDa 
• Atom Count: 11532 
• Modelled Residue Count: 1522 
• Deposited Residue Count: 1616 
• Unique protein chains: 1

4ISY

Crystal structure of IscS from Mycobacterium tuberculosis

• PDB DOI: 10.2210/pdb4ISY/pdb

• Classification: TRANSFERASE
• Organism(s): Mycobacterium tuberculosis
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2013-01-17 Released: 2014-02-26 
• Deposition Author(s): Rybniker, J., Pojer, F., Cole, S.T.

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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 

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

• PubMed: 24548275 
• 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. 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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Organizational Affiliation: 

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

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Cysteine desulfurase	A, B, C, D	404	Mycobacterium tuberculosis	Mutation(s): 0  Gene Names: iscS, MT3109, Rv3025c EC: 2.8.1.7
UniProt
Find proteins for P9WQ71 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)) Explore P9WQ71  Go to UniProtKB:  P9WQ71

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
SO4	J [auth C]	SULFATE ION O4 S QAOWNCQODCNURD-UHFFFAOYSA-L
GOL	E [auth A], F [auth A], G [auth A], H [auth B], I [auth B], K [auth C], L [auth C], M [auth C]	GLYCEROL C3 H8 O3 PEDCQBHIVMGVHV-UHFFFAOYSA-N

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
LLP	A, B, C, D	L-PEPTIDE LINKING	C14 H22 N3 O7 P		LYS

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 = 66.814	α = 94.54
b = 78.131	β = 104.71
c = 92.774	γ = 98.57

Software Package:

Software Name	Purpose
XDS	data scaling
PHASER	phasing
REFMAC	refinement
XDS	data reduction

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2013-01-17 
• Released Date: 2014-02-26 
Deposition Author(s): Rybniker, J., Pojer, F., Cole, S.T.

Revision History  

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