7QF4

Structure of the R57Q mutant of miniSOG expressed in E. coli in LB medium enriched with riboflavin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.17 Å
  • R-Value Free: 0.182 
  • R-Value Work: 0.146 

Starting Model: experimental
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This is version 1.2 of the entry. See complete history


Literature

Riboflavin-binding proteins for singlet oxygen production.

Lafaye, C.Aumonier, S.Torra, J.Signor, L.von Stetten, D.Noirclerc-Savoye, M.Shu, X.Ruiz-Gonzalez, R.Gotthard, G.Royant, A.Nonell, S.

(2022) Photochem Photobiol Sci 21: 1545-1555

  • DOI: https://doi.org/10.1007/s43630-021-00156-1
  • Primary Citation of Related Structures:  
    7QF2, 7QF3, 7QF4, 7QF5

  • PubMed Abstract: 

    miniSOG, developed as the first fully genetically encoded singlet oxygen photosensitiser, has found various applications in cell imaging and functional studies. Yet, miniSOG has suboptimal properties, including a low yield of singlet oxygen generation, which can nevertheless be improved tenfold upon blue light irradiation. In a previous study, we showed that this improvement was due to the photolysis of the miniSOG chromophore, flavin mononucleotide (FMN), into lumichrome, with concomitant removal of the phosphoribityl tail, thereby improving oxygen access to the alloxazine ring. We thus reasoned that a chromophore with a shorter tail would readily improve the photosensitizing properties of miniSOG. In this work, we show that the replacement of FMN by riboflavin (RF), which lacks the bulky phosphate group, significantly improves the singlet oxygen quantum yield (Φ Δ ). We then proceeded to mutagenize the residues stabilizing the phosphate group of FMN to alter the chromophore specificity. We identified miniSOG-R57Q as a flavoprotein that selectively binds RF in cellulo, with a modestly improved Φ Δ . Our results show that it is possible to modify the flavin specificity of a given flavoprotein, thus providing a new option to tune its photophysical properties, including those leading to photosensitization. We also determined the structure of miniSOG-Q103L, a mutant with a much increased Φ Δ , which allowed us to postulate the existence of another access channel to FMN for molecular oxygen.


  • Organizational Affiliation

    Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), 71 Avenue des Martyrs, 38044, Grenoble Cedex 9, France.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
miniSOG (R57Q mutant)A [auth AAA]128Arabidopsis thalianaMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.17 Å
  • R-Value Free: 0.182 
  • R-Value Work: 0.146 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 39.93α = 90
b = 39.93β = 90
c = 134.65γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
XSCALEdata scaling
PHASERphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Agence Nationale de la Recherche (ANR)FranceANR-11-JSV5-0009

Revision History  (Full details and data files)

  • Version 1.0: 2022-02-16
    Type: Initial release
  • Version 1.1: 2022-09-28
    Changes: Database references, Derived calculations
  • Version 1.2: 2024-01-31
    Changes: Data collection, Refinement description