9I2I | pdb_00009i2i

X-ray structure of the B1 domain of streptococcal protein G triple mutant T2Q, N8D, and N37D (GB1-QDD).

• PDB DOI: https://doi.org/10.2210/pdb9I2I/pdb

• Classification: IMMUNE SYSTEM
• Organism(s): Streptococcus sp.
• Expression System: Escherichia coli
• Mutation(s): Yes 


• Deposited: 2025-01-20 Released: 2025-09-03 
• Deposition Author(s): Engilberge, S., Becker, L.M., Kapitonova, A., Schanda, P.
• Funding Organization(s): Austrian Science Fund

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.08 Å
• R-Value Free: 
  0.210 (Depositor), 0.209 (DCC) 
• R-Value Work: 
  0.180 (Depositor), 0.180 (DCC) 
• R-Value Observed: 
  0.181 (Depositor) 

Starting Model: in silico

Literature

Aromatic Ring Flips Reveal Reshaping of Protein Dynamics in Crystals and Complexes

Becker, L.M., Fu, H., Tatman, B.P., Dreydoppel, M., Kapitonova, A., Weininger, U., Engilberge, S., Chipot, C., Schanda, P.

(2025) bioRxiv 

• DOI: https://doi.org/10.1101/2025.08.20.671406

Biological Assembly 1  

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

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: gel filtration

Biological Assembly 2  

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

Biological assembly 2 assigned by authors.

Macromolecule Content 

• Total Structure Weight: 12.48 kDa 
• Atom Count: 1,050 
• Modeled Residue Count: 110 
• Deposited Residue Count: 112 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Immunoglobulin G-binding protein G	A, B	56	Streptococcus sp.	Mutation(s): 3  Gene Names: spg
UniProt
Find proteins for P19909 (Streptococcus sp. group G) Explore P19909  Go to UniProtKB:  P19909

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
NA	C [auth B]	SODIUM ION Na FKNQFGJONOIPTF-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.08 Å
• R-Value Free:  0.210 (Depositor), 0.209 (DCC) 
• R-Value Work:  0.180 (Depositor), 0.180 (DCC) 
• R-Value Observed: 0.181 (Depositor) 

Space Group: C 1 2 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 77.48	α = 90
b = 35.186	β = 122.512
c = 49.943	γ = 90

Software Package:

Software Name	Purpose
PHENIX	refinement
XDS	data reduction
Aimless	data scaling
PHASER	phasing

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2025-09-03 
Deposition Author(s): Engilberge, S., Becker, L.M., Kapitonova, A., Schanda, P.

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Funding Organization	Location	Grant Number
Austrian Science Fund	Austria	--

Revision History  

• Version 1.0: 2025-09-03
  Type: Initial release
  
• Version 1.1: 2025-10-22
  Changes: Data collection