3HUG

Crystal structure of Mycobacterium tuberculosis anti-sigma factor RslA in complex with -35 promoter binding domain of sigL


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.260 
  • R-Value Work: 0.211 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural and biochemical bases for the redox sensitivity of Mycobacterium tuberculosis RslA

Thakur, K.G.Praveena, T.Gopal, B.

(2010) J.Mol.Biol. 397: 1199-1208

  • DOI: 10.1016/j.jmb.2010.02.026

  • PubMed Abstract: 
  • An effective transcriptional response to redox stimuli is of particular importance for Mycobacterium tuberculosis, as it adapts to the environment of host alveoli and macrophages. The M. tuberculosis sigma factor sigma(L) regulates the expression of ...

    An effective transcriptional response to redox stimuli is of particular importance for Mycobacterium tuberculosis, as it adapts to the environment of host alveoli and macrophages. The M. tuberculosis sigma factor sigma(L) regulates the expression of genes involved in cell-wall and polyketide syntheses. sigma(L) interacts with the cytosolic anti-sigma domain of a membrane-associated protein, RslA. Here we demonstrate that RslA binds Zn(2+) and can sequester sigma(L) in a reducing environment. In response to an oxidative stimulus, proximal cysteines in the CXXC motif of RslA form a disulfide bond, releasing bound Zn(2+). This results in a substantial rearrangement of the sigma(L)/RslA complex, leading to an 8-fold decrease in the affinity of RslA for sigma(L). The crystal structure of the -35-element recognition domain of sigma(L), sigma(4)(L), bound to RslA reveals that RslA inactivates sigma(L) by sterically occluding promoter DNA and RNA polymerase binding sites. The crystal structure further reveals that the cysteine residues that coordinate Zn(2+) in RslA are solvent exposed in the complex, thus providing a structural basis for the redox sensitivity of RslA. The biophysical parameters of sigma(L)/RslA interactions provide a template for understanding how variations in the rate of Zn(2+) release and associated conformational changes could regulate the activity of a Zn(2+)-associated anti-sigma factor.


    Organizational Affiliation

    Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
RNA polymerase sigma factor
A, C, E, G, I, K, M, O, Q, S
92Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)Mutation(s): 0 
Gene Names: sigL
Find proteins for P9WGH5 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Go to UniProtKB:  P9WGH5
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
PROBABLE CONSERVED MEMBRANE PROTEIN
B, D, F, H, J, L, N, P, R, T
108Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)Mutation(s): 0 
Gene Names: rslA
Find proteins for P9WJ67 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Go to UniProtKB:  P9WJ67
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download SDF File 
Download CCD File 
B, D, F, H, J, L, N, P, R, T
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4

Download SDF File 
Download CCD File 
A, C, G, I, L, M, P, Q, S
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.260 
  • R-Value Work: 0.211 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 83.070α = 90.00
b = 166.770β = 90.00
c = 178.870γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
PHENIXmodel building
PHENIXphasing
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-03-02
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2011-09-28
    Type: Database references, Refinement description