4F3E | pdb_00004f3e

Crystal Structure of Thermus thermophilus HB8 CasA

• PDB DOI: https://doi.org/10.2210/pdb4F3E/pdb

• Classification: IMMUNE SYSTEM
• Organism(s): Thermus thermophilus HB8
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2012-05-09 Released: 2012-05-23 
• Deposition Author(s): Bailey, S., Mulepati, S.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.40 Å
• R-Value Free: 
  0.251 (Depositor), 0.246 (DCC) 
• R-Value Work: 
  0.195 (Depositor), 0.193 (DCC) 
• R-Value Observed: 
  0.198 (Depositor) 

Literature

Crystal Structure of the Largest Subunit of a Bacterial RNA-guided Immune Complex and Its Role in DNA Target Binding.

Mulepati, S., Orr, A., Bailey, S.

(2012) J Biological Chem 287: 22445-22449

• PubMed: 22621933 
• DOI: https://doi.org/10.1074/jbc.C112.379503
• Primary Citation Related Structures: 
  4F3E


• PubMed Abstract: 
  

  Prokaryotes make use of small RNAs encoded by CRISPR (clustered regularly interspaced short palindromic repeat) loci to provide immunity against bacteriophage or plasmid invasion. In Escherichia coli, the CRISPR-associated complex for antiviral defense (Cascade) utilizes these RNAs to target foreign DNA for destruction. CasA, the largest subunit of Cascade, is essential for its function. Here we report the crystal structure of Thermus thermophilus CasA. The structure is composed of two domains that are arranged in a chair-like conformation with a novel fold forming the larger N-terminal domain. Docking of the crystal structure into cryo-electron microscopy maps reveals two loops in CasA that likely have important functions in DNA target binding. Finally, DNA binding experiments show that CasA is essential for binding of Cascade to DNA target.

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Organizational Affiliation: 
• Department of Biochemistry and Molecular Biology, Johns Hopkins School of Public Health, Baltimore, Maryland 21205, USA.

Biological Assembly 1  

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

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

Biological Assembly 2  

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

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

Macromolecule Content 

• Total Structure Weight: 112.55 kDa 
• Atom Count: 7,835 
• Modeled Residue Count: 946 
• Deposited Residue Count: 1,004 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
CasA	A, B	502	Thermus thermophilus HB8	Mutation(s): 0  Gene Names: TTHB188
UniProt
Find proteins for Q53VY1 (Thermus thermophilus (strain ATCC 27634 / DSM 579 / HB8)) Explore Q53VY1  Go to UniProtKB:  Q53VY1

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.40 Å
• R-Value Free:  0.251 (Depositor), 0.246 (DCC) 
• R-Value Work:  0.195 (Depositor), 0.193 (DCC) 
• R-Value Observed: 0.198 (Depositor) 

Space Group: P 1 2₁ 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 93.888	α = 90
b = 47.926	β = 97.52
c = 129.168	γ = 90

Software Package:

Software Name	Purpose
Blu-Ice	data collection
SOLVE	phasing
PHENIX	refinement
HKL-2000	data reduction
HKL-2000	data scaling

Structure Validation

Entry History 

Deposition Data

• Released Date: 2012-05-23 
Deposition Author(s): Bailey, S., Mulepati, S.

Revision History  

• Version 1.0: 2012-05-23
  Type: Initial release
  
• Version 1.1: 2012-06-06
  Changes: Database references
• Version 1.2: 2012-07-18
  Changes: Database references
• Version 1.3: 2024-10-30
  Changes: Data collection, Database references, Refinement description, Structure summary