7qf4

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

spinqualitylabelsall models 7qf4, resolution 1.17Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7qf4 is a 1 chain structure with sequence from Arabidopsis thaliana. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.17Å Ligands: CL, CO, RBF Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed 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 (PhiDelta). 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 PhiDelta. 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 PhiDelta, which allowed us to postulate the existence of another access channel to FMN for molecular oxygen. 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 Photochem Photobiol Sci. 2022 Jan 18. pii: 10.1007/s43630-021-00156-1. doi:, 10.1007/s43630-021-00156-1. PMID:35041199 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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