Biological Assembly 1  

 3D View: Structure | 1D-3D View | Electron Density | Validation Report

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

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

Macromolecule Content

• Total Structure Weight: 27.70 kDa 
• Atom Count: 2140 
• Modelled Residue Count: 237 
• Deposited Residue Count: 243 
• Unique protein chains: 1

3ZTF

X-ray Structure of the Cyan Fluorescent Protein mTurquoise2 (K206A mutant)

• PDB DOI: 10.2210/pdb3ZTF/pdb

• Classification: FLUORESCENT PROTEIN
• Organism(s): Aequorea victoria
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): Yes 


• Deposited: 2011-07-07 Released: 2012-03-21 
• Deposition Author(s): von Stetten, D., Goedhart, J., Noirclerc-Savoye, M., Lelimousin, M., Joosen, L., Hink, M.A., van Weeren, L., Gadella, T.W.J., Royant, A.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.31 Å
• R-Value Free: 0.177 
• R-Value Work: 0.132 
• R-Value Observed: 0.134 

Literature

Structure-Guided Evolution of Cyan Fluorescent Proteins Towards a Quantum Yield of 93%

Goedhart, J., von Stetten, D., Noirclerc-Savoye, M., Lelimousin, M., Joosen, L., Hink, M.A., van Weeren, L., Gadella, T.W.J., Royant, A.

(2012) Nat Commun 3: 751

• PubMed: 22434194 
• DOI: 10.1038/ncomms1738
• Primary Citation of Related Structures:  
  2YDZ, 2YE0, 3ZTF


• PubMed Abstract: 
  

Cyan variants of green fluorescent protein are widely used as donors in Förster resonance energy transfer experiments. The popular, but modestly bright, Enhanced Cyan Fluorescent Protein (ECFP) was sequentially improved into the brighter variants Super Cyan Fluorescent Protein 3A (SCFP3A) and mTurquoise, the latter exhibiting a high-fluorescence quantum yield and a long mono-exponential fluorescence lifetime. Here we combine X-ray crystallography and excited-state calculations to rationalize these stepwise improvements. The enhancement originates from stabilization of the seventh β-strand and the strengthening of the sole chromophore-stabilizing hydrogen bond. The structural analysis highlighted one suboptimal internal residue, which was subjected to saturation mutagenesis combined with fluorescence lifetime-based screening. This resulted in mTurquoise2, a brighter variant with faster maturation, high photostability, longer mono-exponential lifetime and the highest quantum yield measured for a monomeric fluorescent protein. Together, these properties make mTurquoise2 the preferable cyan variant of green fluorescent protein for long-term imaging and as donor for Förster resonance energy transfer to a yellow fluorescent protein.

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Related Citations: 

• Bright Cyan Fluorescent Protein Variants Identified by Fluorescence Lifetime Screening.
  Goedhart, J., van Weeren, L., Hink, M.A., Vischer, N.O.E., Jalink, K., Gadella, T.W.J.J.
  (2010) Nat Methods 7: 137

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Organizational Affiliation: 

Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, 1098 XH Amsterdam, The Netherlands.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
GREEN FLUORESCENT PROTEIN	A	243	Aequorea victoria	Mutation(s): 9  Gene Names: GFP
UniProt
Find proteins for P42212 (Aequorea victoria) Explore P42212  Go to UniProtKB:  P42212

Small Molecules

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
SWG	A	L-PEPTIDE LINKING	C16 H16 N4 O4		SER, TRP, GLY

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.31 Å
• R-Value Free: 0.177 
• R-Value Work: 0.132 
• R-Value Observed: 0.134 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 51.01	α = 90
b = 62.549	β = 90
c = 70.356	γ = 90

Software Package:

Software Name	Purpose
REFMAC	refinement
XDS	data reduction
SCALA	data scaling
REFMAC	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2011-07-07 
• Released Date: 2012-03-21 
Deposition Author(s): von Stetten, D., Goedhart, J., Noirclerc-Savoye, M., Lelimousin, M., Joosen, L., Hink, M.A., van Weeren, L., Gadella, T.W.J., Royant, A.

Revision History  

• Version 1.0: 2012-03-21
  Type: Initial release
  
• Version 1.1: 2012-04-04
  Changes: Other
• Version 1.2: 2017-09-27
  Changes: Data collection
• Version 1.3: 2017-12-20
  Changes: Database references
• Version 1.4: 2019-10-23
  Changes: Data collection, Database references, Derived calculations, Other