Biological Assembly 1  

 3D View: Structure | Electron Density

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

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 7.38 kDa 
• Atom Count: 537 
• Residue Count: 67 
• Unique protein chains: 1

2I5L

Crystal structure of Bacillus subtilis Cold Shock Protein variant Bs-CspB M1R/E3K/K65I

• DOI: 10.2210/pdb2I5L/pdb

• Classification: GENE REGULATION
• Organism(s): Bacillus subtilis
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): Yes 


• Deposited: 2006-08-25 Released: 2007-05-22 
• Deposition Author(s): Max, K.E.A., Heinemann, U.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.55 Å
• R-Value Free: 0.244 
• R-Value Work: 0.227 

Literature

Optimized variants of the cold shock protein from in vitro selection: structural basis of their high thermostability.

Max, K.E., Wunderlich, M., Roske, Y., Schmid, F.X., Heinemann, U.

(2007) J Mol Biol 369: 1087-1097

• PubMed: 17481655 
• DOI: 10.1016/j.jmb.2007.04.016
• Primary Citation of Related Structures:  
  2I5M, 2I5L


• PubMed Abstract: 
  

The bacterial cold shock proteins (Csp) are widely used as models for the experimental and computational analysis of protein stability. In a previous study, in vitro evolution was employed to identify strongly stabilizing mutations in Bs-CspB from Bacillus subtilis. The best variant found by this approach contained the mutations M1R, E3K and K65I, which raised the midpoint of thermal unfolding of Bs-CspB from 53.8 degrees C to 83.7 degrees C, and increased the Gibbs free energy of stabilization by 20.9 kJ mol(-1). Another selected variant with the two mutations A46K and S48R was stabilized by 11.1 kJ mol(-1). To elucidate the molecular basis of these stabilizations, we determined the crystal structures of these two Bs-CspB variants. The mutated residues are generally well ordered and provide additional stabilizing interactions, such as charge interactions, additional hydrogen bonds and improved side-chain packing. Several mutations improve the electrostatic interactions, either by the removal of unfavorable charges (E3K) or by compensating their destabilizing interactions (A46K, S48R). The stabilizing mutations are clustered at a contiguous surface area of Bs-CspB, which apparently is critically important for the stability of the beta-barrel structure but not well optimized in the wild-type protein.

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Organizational Affiliation: 

Makromolekulare Strukturen und Interaktionen, Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Cold shock protein cspB	X	67	Bacillus subtilis	Mutation(s): 3  Gene Names: cspB, cspA
Find proteins for P32081 (Bacillus subtilis (strain 168)) Explore P32081  Go to UniProtKB:  P32081

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.55 Å
• R-Value Free: 0.244 
• R-Value Work: 0.227 
• Space Group: P 4₃ 2₁ 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 55.5	α = 90
b = 55.5	β = 90
c = 55.47	γ = 90

Software Package:

Software Name	Purpose
XSCALE	data scaling
AMoRE	phasing
REFMAC	refinement
PDB_EXTRACT	data extraction
MAR345	data collection
XDS	data reduction

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2006-08-25 
• Released Date: 2007-05-22 
Deposition Author(s): Max, K.E.A., Heinemann, U.

Revision History 

• Version 1.0: 2007-05-22
  Type: Initial release
  
• Version 1.1: 2008-05-01
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2017-10-18
  Changes: Refinement description