Related Experiment Video
Updated: May 11, 2026
06:42
Structure Solution of the Fluorescent Protein Cerulean Using MeshAndCollect
Published on: March 19, 2019
The 1.6 Å resolution structure of a FRET-optimized Cerulean fluorescent protein
Jennifer L Watkins1, Hanseong Kim, Michele L Markwardt
1Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, USA.
Summary
The crystal structure of mCerulean3, an optimized Förster resonance energy transfer (FRET) donor, reveals a planar chromophore and reduced heterogeneity. This structural insight explains its superior photophysical properties for live cell imaging.
Area of Science:
- Biophysics
- Structural Biology
- Fluorescence Microscopy
Background:
- Genetically encoded cyan fluorescent proteins (CFPs) are vital for Förster resonance energy transfer (FRET) in live cell imaging.
- Protein heterogeneity and structural variations have historically limited CFP photophysical properties.
- mCerulean3, an enhanced CFP variant, offers improved quantum yield and reduced heterogeneity.
Purpose of the Study:
- To elucidate the 1.6 Å resolution X-ray structure of the mCerulean3 fluorescent protein.
- To understand the structural basis for mCerulean3's enhanced photophysical properties.
- To identify structural differences and similarities compared to mTurquoise2.
Main Methods:
- X-ray crystallography at 1.6 Å resolution.
- Analysis of chromophore configuration and protein structural elements.
- Comparison of mCerulean3 structure with related fluorescent proteins.
Main Results:
- The mCerulean3 chromophore adopts a planar trans configuration, eliminating acid-induced isomerization.
- Reduced conformational heterogeneity was observed in β-Strand 7 near the chromophore.
- Improved side-chain packing, including the Ser65 reversion mutation's effect, was identified.
Conclusions:
- The determined structure explains mCerulean3's superior performance as a FRET donor.
- Structural stability and homogeneity contribute to enhanced photophysical properties.
- Further engineering strategies can be informed by these structural findings.
