7ZCT

Structure of the red fluorescent protein mScarlet3 at pH 7.5

• PDB DOI: https://doi.org/10.2210/pdb7ZCT/pdb

• Classification: FLUORESCENT PROTEIN
• Organism(s): Discosoma sp.
• Expression System: Escherichia coli
• Mutation(s): Yes 


• Deposited: 2022-03-28 Released: 2023-04-05 
• Deposition Author(s): Aumonier, S., Dupuy, J., Royant, A.
• Funding Organization(s): Agence Nationale de la Recherche (ANR)

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.33 Å
• R-Value Free: 0.228 
• R-Value Work: 0.200 
• R-Value Observed: 0.200 

Starting Model: experimental

Literature

mScarlet3: a brilliant and fast-maturing red fluorescent protein.

Gadella Jr., T.W.J., van Weeren, L., Stouthamer, J., Hink, M.A., Wolters, A.H.G., Giepmans, B.N.G., Aumonier, S., Dupuy, J., Royant, A.

(2023) Nat Methods 20: 541-545

• PubMed: 36973546 
• DOI: https://doi.org/10.1038/s41592-023-01809-y
• Primary Citation of Related Structures:  
  7ZCT


• PubMed Abstract: 
  

  We report the evolution of mScarlet3, a cysteine-free monomeric red fluorescent protein with fast and complete maturation, as well as record brightness, quantum yield (75%) and fluorescence lifetime (4.0 ns). The mScarlet3 crystal structure reveals a barrel rigidified at one of its heads by a large hydrophobic patch of internal residues. mScarlet3 behaves well as a fusion tag, displays no apparent cytotoxicity and it surpasses existing red fluorescent proteins as a Förster resonance energy transfer acceptor and as a reporter in transient expression systems.

---

Organizational Affiliation: 

Section of Molecular Cytology and van Leeuwenhoek Centre for Advanced Microscopy, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands. [e-mail].

Biological Assembly 1  

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

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: assay for oligomerization

Biological Assembly 2  

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

Biological assembly 2 assigned by authors.

Macromolecule Content

• Total Structure Weight: 51.73 kDa 
• Atom Count: 3,883 
• Modelled Residue Count: 430 
• Deposited Residue Count: 454 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Red fluorescent protein drFP583	A, B	227	Discosoma sp.	Mutation(s): 48
UniProt
Find proteins for Q9U6Y8 (Discosoma sp.) Explore Q9U6Y8  Go to UniProtKB:  Q9U6Y8

Small Molecules

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
NRQ	A, B	L-PEPTIDE LINKING	C16 H17 N3 O4 S		MET, TYR, GLY

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.33 Å
• R-Value Free: 0.228 
• R-Value Work: 0.200 
• R-Value Observed: 0.200 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 59.231	α = 90
b = 61.862	β = 90
c = 110.933	γ = 90

Software Package:

Software Name	Purpose
XDS	data reduction
XDS	data scaling
PHASER	phasing
REFMAC	refinement
PDB_EXTRACT	data extraction

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2023-04-05 
Deposition Author(s): Aumonier, S., Dupuy, J., Royant, A.

---

Funding Organization	Location	Grant Number
Agence Nationale de la Recherche (ANR)	France	ANR-17-CE11-0013

Revision History  

• Version 1.0: 2023-04-05
  Type: Initial release
  
• Version 1.1: 2023-04-19
  Changes: Database references
• Version 1.2: 2024-02-07
  Changes: Data collection, Refinement description