2ASB | pdb_00002asb

Structure of a Mycobacterium tuberculosis NusA-RNA complex

• PDB DOI: https://doi.org/10.2210/pdb2ASB/pdb
• NAKB: 2ASB

• Classification: transcription/RNA
• Organism(s): Mycobacterium tuberculosis
• Expression System: Escherichia coli BL21
• Mutation(s): No 


• Deposited: 2005-08-23 Released: 2005-10-11 
• Deposition Author(s): Beuth, B., Pennell, S., Arnvig, K.B., Martin, S.R., Taylor, I.A.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.50 Å
• R-Value Free: 
  0.222 (Depositor), 0.190 (DCC) 
• R-Value Work: 
  0.188 (Depositor), 0.190 (DCC) 
• R-Value Observed: 
  0.190 (Depositor) 

Starting Model: experimental

Literature

Structure of a Mycobacterium tuberculosis NusA-RNA complex.

Beuth, B., Pennell, S., Arnvig, K.B., Martin, S.R., Taylor, I.A.

(2005) EMBO J 24: 3576-3587

• PubMed: 16193062 
• DOI: https://doi.org/10.1038/sj.emboj.7600829
• Primary Citation Related Structures: 
  2ASB, 2ATW


• PubMed Abstract: 
  

  NusA is a key regulator of bacterial transcriptional elongation, pausing, termination and antitermination, yet relatively little is known about the molecular basis of its activity in these fundamental processes. In Mycobacterium tuberculosis, NusA has been shown to bind with high affinity and specificity to BoxB-BoxA-BoxC antitermination sequences within the leader region of the single ribosomal RNA (rRNA) operon. We have determined high-resolution X-ray structures of a complex of NusA with two short oligo-ribonucleotides derived from the BoxC stem-loop motif and have characterised the interaction of NusA with a variety of RNAs derived from the antitermination region. These structures reveal the RNA bound in an extended conformation to a large interacting surface on both KH domains. Combining structural data with observed spectral and calorimetric changes, we now show that NusA binding destabilises secondary structure within rRNA antitermination sequences and propose a model where NusA functions as a chaperone for nascently forming RNA structures.

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Organizational Affiliation: 
• Division of Protein Structure, National Institute for Medical Research, London, UK.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content 

• Total Structure Weight: 30.53 kDa 
• Atom Count: 2,183 
• Modeled Residue Count: 237 
• Deposited Residue Count: 262 
• Unique protein chains: 1
• Unique nucleic acid chains: 1

Macromolecules

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Transcription elongation protein nusA	B [auth A]	251	Mycobacterium tuberculosis	Mutation(s): 0  Gene Names: nusA
UniProt
Find proteins for P9WIV3 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)) Explore P9WIV3  Go to UniProtKB:  P9WIV3

Entity ID: 1
Molecule	Chains	Length	Organism	Image
ribosomal RNA (5'- GAACUCAAUAG -3')	A [auth B]	11	N/A

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.50 Å
• R-Value Free:  0.222 (Depositor), 0.190 (DCC) 
• R-Value Work:  0.188 (Depositor), 0.190 (DCC) 
• R-Value Observed: 0.190 (Depositor) 

Space Group: P 4₁ 2 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 71.416	α = 90
b = 71.416	β = 90
c = 115.219	γ = 90

Software Package:

Software Name	Purpose
REFMAC	refinement
DENZO	data reduction
SCALEPACK	data scaling
AMoRE	phasing

Structure Validation

Entry History 

Deposition Data

• Released Date: 2005-10-11 
Deposition Author(s): Beuth, B., Pennell, S., Arnvig, K.B., Martin, S.R., Taylor, I.A.

Revision History  

• Version 1.0: 2005-10-11
  Type: Initial release
  
• Version 1.1: 2008-04-30
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2023-08-23
  Changes: Data collection, Database references, Derived calculations, Refinement description