4OHS | pdb_00004ohs

The structure of a far-red fluorescent protein, AQ143

• PDB DOI: https://doi.org/10.2210/pdb4OHS/pdb

• Classification: FLUORESCENT PROTEIN
• Organism(s): Actinia equina
• Mutation(s): No 


• Deposited: 2014-01-17 Released: 2014-02-26 
• Deposition Author(s): Wannier, T.M., Mayo, S.L.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.19 Å
• R-Value Free: 
  0.221 (Depositor), 0.222 (DCC) 
• R-Value Work: 
  0.190 (Depositor), 0.193 (DCC) 
• R-Value Observed: 
  0.191 (Depositor) 

Literature

The structure of a far-red fluorescent protein, AQ143, shows evidence in support of reported red-shifting chromophore interactions.

Wannier, T.M., Mayo, S.L.

(2014) Protein Sci 23: 1148-1153

• PubMed: 24888769 
• DOI: https://doi.org/10.1002/pro.2498
• Primary Citation Related Structures: 
  4OHS


• PubMed Abstract: 
  

  Engineering fluorescent proteins (FPs) to emit light at longer wavelengths is a significant focus in the development of the next generation of fluorescent biomarkers, as far-red light penetrates tissue with minimal absorption, allowing better imaging inside of biological hosts. Structure-guided design and directed evolution have led to the discovery of red FPs with significant bathochromic shifts to their emission. Here, we present the crystal structure of one of the most bathochromically shifted FPs reported to date, AQ143, a nine-point mutant of aeCP597, a chromoprotein from Actinia equina. The 2.19 Å resolution structure reveals several important chromophore interactions that contribute to the protein's far-red emission and shows dual occupancy of the green and red chromophores.

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Organizational Affiliation: 
• Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, 91125.

Biological Assembly 1  

Global Symmetry: Dihedral - D2  (Explore in 3D)
Global Stoichiometry: Homo 4-mer - A4 

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

Biological Assembly 2  

Global Symmetry: Dihedral - D2  (Explore in 3D)
Global Stoichiometry: Homo 4-mer - A4 

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

Macromolecule Content 

• Total Structure Weight: 213.66 kDa 
• Atom Count: 14,612 
• Modeled Residue Count: 1,770 
• Deposited Residue Count: 1,904 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
FAR-RED FLUORESCENT PROTEIN AQ143	A, B, C, D, E, F, G, H	237	Actinia equina	Mutation(s): 0
UniProt
Find proteins for Q2VFP3 (Actinia equina) Explore Q2VFP3  Go to UniProtKB:  Q2VFP3

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CL	I [auth A], J [auth B], K [auth C], L [auth D]	CHLORIDE ION Cl VEXZGXHMUGYJMC-UHFFFAOYSA-M

Modified Residues  2 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
CH6	A, B, C, D, E, F, G, H	L-PEPTIDE LINKING	C16 H19 N3 O4 S		MET, TYR, GLY
NRQ	A, B, C, D, E, F, G, H	L-PEPTIDE LINKING	C16 H17 N3 O4 S		MET, TYR, GLY

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.19 Å
• R-Value Free:  0.221 (Depositor), 0.222 (DCC) 
• R-Value Work:  0.190 (Depositor), 0.193 (DCC) 
• R-Value Observed: 0.191 (Depositor) 

Space Group: P 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 50.967	α = 98.38
b = 68.114	β = 90.74
c = 132.788	γ = 110.47

Software Package:

Software Name	Purpose
PHENIX	refinement

Structure Validation

Entry History 

Deposition Data

• Released Date: 2014-02-26 
Deposition Author(s): Wannier, T.M., Mayo, S.L.

Revision History  

• Version 1.0: 2014-02-26
  Type: Initial release
  
• Version 1.1: 2014-07-02
  Changes: Database references
• Version 1.2: 2014-08-06
  Changes: Database references
• Version 1.3: 2024-11-27
  Changes: Data collection, Database references, Derived calculations, Structure summary