9D57 | pdb_00009d57

iGABASnFR2 fluorescent GABA sensor in complex with GABA

• PDB DOI: https://doi.org/10.2210/pdb9D57/pdb

• Classification: FLUORESCENT PROTEIN
• Organism(s): synthetic construct
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2024-08-13 Released: 2025-08-20 
• Deposition Author(s): Zhang, Y., Looger, L.L.
• Funding Organization(s): Howard Hughes Medical Institute (HHMI)

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.60 Å
• R-Value Free: 
  0.249 (Depositor), 0.244 (DCC) 
• R-Value Work: 
  0.206 (Depositor), 0.202 (DCC) 

Starting Model: experimental

Literature

iGABASnFR2: Improved genetically encoded protein sensors of GABA

Kolb, I., Hasseman, J.P., Matsumoto, A., Jensen, T.P., Kopach, O., Arthur, B.J., Zhang, Y., Tsang, A., Reep, D., Tsegaye, G., Zheng, J., Patel, R.H., Looger, L.L., Marvin, J.S., Korff, W.L., Rusakov, D.A., Yonehara, K., Turner, G.C.

(2025) bioRxiv 

• DOI: https://doi.org/10.1101/2025.03.25.644953

Biological Assembly 1  

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

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: homology

Biological Assembly 2  

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

Biological assembly 2 assigned by authors.

Biological Assembly Evidence: homology

Biological Assembly 3  

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

Biological assembly 3 assigned by authors.

Biological Assembly Evidence: homology

Biological Assembly 4  

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

Biological assembly 4 assigned by authors.

Biological Assembly Evidence: homology

Biological Assembly 5  

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

Biological assembly 5 assigned by authors.

Biological Assembly Evidence: homology

Biological Assembly 6  

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

Biological assembly 6 assigned by authors.

Biological Assembly Evidence: homology

Macromolecule Content 

• Total Structure Weight: 375.5 kDa 
• Atom Count: 24,592 
• Modeled Residue Count: 3,232 
• Deposited Residue Count: 3,384 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
ABC transporter substrate-binding protein, Circular permuted superfolder GFP fusion	A, B, C [auth D], D [auth F], E [auth C], F [auth E]	564	synthetic construct	Mutation(s): 0

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
ABU (Subject of Investigation/LOI)	G [auth A], H [auth B], I [auth D], J [auth F], K [auth C], L [auth E]	GAMMA-AMINO-BUTANOIC ACID C4 H9 N O2 BTCSSZJGUNDROE-UHFFFAOYSA-N

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
CRO	A, B, C [auth D], D [auth F], E [auth C], F [auth E]	L-PEPTIDE LINKING	C15 H17 N3 O5		THR, TYR, GLY

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.60 Å
• R-Value Free:  0.249 (Depositor), 0.244 (DCC) 
• R-Value Work:  0.206 (Depositor), 0.202 (DCC) 

Space Group: P 1 2₁ 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 76.501	α = 90
b = 109.924	β = 100.255
c = 214.309	γ = 90

Software Package:

Software Name	Purpose
REFMAC	refinement
XDS	data reduction
Aimless	data scaling
MOLREP	phasing

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2025-08-20 
Deposition Author(s): Zhang, Y., Looger, L.L.

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Funding Organization	Location	Grant Number
Howard Hughes Medical Institute (HHMI)	United States	--

Revision History  

• Version 1.0: 2025-08-20
  Type: Initial release