2O8X

Crystal structure of the "-35 element" promoter recognition domain of Mycobacterium tuberculosis SigC


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.271 
  • R-Value Work: 0.214 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Structural and biophysical studies on two promoter recognition domains of the extra-cytoplasmic function sigma factor sigma(C) from Mycobacterium tuberculosis.

Thakur, K.G.Joshi, A.M.Gopal, B.

(2007) J.Biol.Chem. 282: 4711-4718

  • DOI: 10.1074/jbc.M606283200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • sigma factors are transcriptional regulatory proteins that bind to the RNA polymerase and dictate gene expression. The extracytoplasmic function (ECF) sigma factors govern the environment dependent regulation of transcription. ECF sigma factors have ...

    sigma factors are transcriptional regulatory proteins that bind to the RNA polymerase and dictate gene expression. The extracytoplasmic function (ECF) sigma factors govern the environment dependent regulation of transcription. ECF sigma factors have two domains sigma(2) and sigma(4) that recognize the -10 and -35 promoter elements. However, unlike the primary sigma factor sigma(A), the ECF sigma factors lack sigma(3), a region that helps in the recognition of the extended -10 element and sigma(1.1), a domain involved in the autoinhibition of sigma(A) in the absence of core RNA polymerase. Mycobacterium tuberculosis sigma(C) is an ECF sigma factor that is essential for the pathogenesis and virulence of M. tuberculosis in the mouse and guinea pig models of infection. However, unlike other ECF sigma factors, sigma(C) does not appear to have a regulatory anti-sigma factor located in the same operon. We also note that M. tuberculosis sigma(C) differs from the canonical ECF sigma factors as it has an N-terminal domain comprising of 126 amino acids that precedes the sigma(C)(2) and sigma(C)(4) domains. In an effort to understand the regulatory mechanism of this protein, the crystal structures of the sigma(C)(2) and sigma(C)(4) domains of sigma(C) were determined. These promoter recognition domains are structurally similar to the corresponding domains of sigma(A) despite the low sequence similarity. Fluorescence experiments using the intrinsic tryptophan residues of sigma(C)(2) as well as surface plasmon resonance measurements reveal that the sigma(C)(2) and sigma(C)(4) domains interact with each other. Mutational analysis suggests that the Pribnow box-binding region of sigma(C)(2) is involved in this interdomain interaction. Interaction between the promoter recognition domains in M. tuberculosis sigma(C) are thus likely to regulate the activity of this protein even in the absence of an anti-sigma factor.


    Organizational Affiliation

    Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Probable RNA polymerase sigma-C factor
A, B, C
70Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)Mutation(s): 0 
Gene Names: sigC
Find proteins for P9WGH1 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Go to UniProtKB:  P9WGH1
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A, B, C
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.271 
  • R-Value Work: 0.214 
  • Space Group: F 2 3
Unit Cell:
Length (Å)Angle (°)
a = 161.330α = 90.00
b = 161.330β = 90.00
c = 161.330γ = 90.00
Software Package:
Software NamePurpose
MOSFLMdata reduction
MAR345data collection
CCP4data scaling
MOLREPphasing
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-12-26
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Source and taxonomy, Version format compliance
  • Version 1.3: 2017-10-18
    Type: Refinement description