6U1A image
Deposition Date 2019-08-15
Release Date 2020-04-22
Last Version Date 2023-11-15
Entry Detail
PDB ID:
6U1A
Title:
Crystal Structure of Fluorescent Protein FusionRed
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
1.09 Å
R-Value Free:
0.14
R-Value Work:
0.12
R-Value Observed:
0.12
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Red fluorescent protein
Chain IDs:A
Chain Length:232
Number of Molecules:1
Biological Source:Entacmaea quadricolor
Primary Citation
Two independent routes of post-translational chemistry in fluorescent protein FusionRed.
Int.J.Biol.Macromol. 155 551 559 (2020)
PMID: 32243936 DOI: 10.1016/j.ijbiomac.2020.03.244

Abstact

The crystal structure of monomeric red fluorescent protein FusionRed (λex/λem 580/608 mn) has been determined at 1.09 Å resolution and revealed two alternative routes of post-translational chemistry, resulting in distinctly different products. The refinement occupancies suggest the 60:40 ratio of the mature Met63-Tyr64-Gly65 chromophore and uncyclized chromophore-forming tripeptide with the protein backbone cleaved between Met63 and the preceding Phe62 and oxidized Cα-Cβ bond of Tyr64. We analyzed the structures of FusionRed and several related red fluorescent proteins, identified structural elements causing hydrolysis of the peptide bond, and verified their impact by single point mutagenesis. These findings advance the understanding of the post-translational chemistry of GFP-like fluorescent proteins beyond the canonical cyclization-dehydration-oxidation mechanism. They also show that impaired cyclization does not prevent chromophore-forming tripeptide from further transformations enabled by the same set of catalytic residues. Our mutagenesis efforts resulted in inhibition of the peptide backbone cleavage, and a FusionRed variant with ~30% improved effective brightness.

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Primary Citation of related structures