Department of Biophotonics
Groups in the department:
The Department of Biophotonics was established in March 2020 from units previously included in the Department of Genomics and Postgenomic Technologies, the Department of Peptide and Protein Technologies, and the Department of Biomolecular Chemistry.
The department works on fundamental and applied problems in the field of biophotonics using a wide range of approaches: gene engineering, directed molecular evolution, protein chemistry, fluorescence microscopy, X-ray structural analysis of proteins, chemical synthesis.
- Development of technologies for fluorescent labeling of living cells and organisms
- Development of opto- and chemogenetics methods
- Solving crystal structures of fluorescent proteins
- Design of new fluorescent proteins
- Development of super-resolution fluorescence microscopy methods
- Synthesis of fluorescent and fluorogenic compound
Fluorescent biomarker with Ala residue in the third position of the chromophore-forming triad. X-ray study.
The three-dimensional structure and structure-functional relation of four fluorescent proteins, LanFP6G, LanFP6A, LanFP10G and LanFP10A, from the poorly studied chordate group (Branchiostoma floridae) were determined with a resolution 1.20, 1.35, 1.30 and 1.81Å, respectively. We determined the first structure of the GFP-like fluorescent protein, LanFP10A, having matured chromophore with Ala residue in the third position instead of the strictly conserved Gly.
- (2019). Structural Factors Enabling Successful GFP-Like Proteins with Alanine as the Third Chromophore-Forming Residue. J Mol Biol 431 (7), 1397–1408
New labels and approaches for low toxic fluorescent labeling of proteins in living cells
Ultraviolet, often used in fluorescence microscopy and nanoscopy, is extremely toxic to cells. Therefore, it is preferable to use labels in the green and red spectral regions.
We found the ability of the fluorescent protein mAvicFP1 to spontaneously blink under the influence of less toxic blue light, and applied this property to nanoscopy and to track single molecules of labeled proteins in living cells.
Fluorogen-activating proteins are new generation labeling systems based on transient interaction of a genetically encoded protein and externally applied fluorogen. We have created and used in living cells a new red fluorogen N871b for the FAST reporter protein.
- (2019). Live-cell nanoscopy with spontaneous blinking of conventional green fluorescent proteins. Biochem Biophys Res Commun 522 (4), 852–854
- (2019). Red-shifted substrates for FAST fluorogen-activating protein based on the GFP-like chromophores. Chemistry 25 (41), 9592–9596
Tree dimensional structure and structure-functional relation of the green fluorescent protein WasCFP.
The three-dimensional structure of the pH dependent green fluorescent protein of WasCFP with the Trp based chromophore has been determined by X-ray method (resolution 1.3Å) at extremely low value of pH 2.0 (earlier, we determined the crystal structures of WasCFP at pH 10.0, 8.0 и 5.5). It was shown, that stepwise shift of pH from 10.0 to 2.0 is accompanied by the synchronous change of side chain conformations of residues from the chromophore nearest environment. Role of interactions of the chromophore with the key amino-acid residues from nearest environment has been studied by quantum chemistry calculations.
- (2018). Crystal Structure of the pH-Dependent Green Fluorescent Protein WasCFP with a Tryptophan-Based Chromophore at an Extremely Low pH of 2.0. Bioorg Khim 44 (6), 635–639
Photoswitchable red fluorescent proteins for nanoscopy of live cells
We developed new reversibly photoswitchable red fluorescent proteins based on FusionRed. These proteins, rsFusionRed1, 2 and 3, can be switched OFF and ON and by orange and green light, respectively. This photoswitching behavior allows to avoid illumination by phototoxic violet and blue light, which is commonly used for other photoswitchable proteins. Due to high brightness, high photostability, rapid photoswitching and low phototoxic excitation wavelengths rsFusionReds represent excellent tags for nanoscale imaging of living cells.
- (2018). Fast reversibly photoswitching red fluorescent proteins for live-cell RESOLFT nanoscopy. Nat Methods 15 (8), 601–604
Crystal structure of the protein protease inhibitor Alocasin from the rhizomes Alocasia
Three dimensional structure of the β-structural protein Alocasin from the rhizomes Alocasia has been determined by X-ray method at 2.5 Å resolution. Alocasin demonstrates the profound inhibitory activity towards trypsin and chymotrypsin and to midgut proteases of the mosquitos (Aedes aegypti) and presents a promising tool for the anti Ae. aegypti activity.
- (2018). Crystal structure of a novel Kunitz type inhibitor, alocasin with anti-Aedes aegypti activity targeting midgut proteases. Pest Manag Sci 74 (12), 2761–2772
A method of protein labeling in live cells based on fluorogen and fluorogen-binding protein
We developed a new method of target protein labeling called Protein-PAINT. This method is based on reversible binding of a protein domain with a fluorogenic dye that leads to a strong increase in fluorescence intensity. Using computer molecular docking we engineered three mutants of bacterial lipocalin Blc with different affinities to the fluorogen. It was shown that the fluorogen enters live cell quickly and stains target proteins fused with the Blc mutants. The new method ensures an order of magnitude higher photostability of the fluorescence signal in comparison with fluorescent proteins. Protein-PAINT also enables prolonged super-resolution fluorescence microscopy of living cells in both single molecule detection and stimulated emission depletion regimes.
- (2017). Protein labeling for live cell fluorescence microscopy with a highly photostable renewable signal. Chem Sci 8 (10), 7138–7142
Three-dimensional structure and structure-functional relations of fluorescent proteins
Fig. legend: (A) Superimposed structures of miRFP703 (in green) and miRFP709 (in red) showing chromophores in the binding pocket. (B) Emission spectra of miRFP703 (in green), miRFP709 (in red), and miRFP709/Y210F (in magenta)
Three new bright far-red and near infrared genetically engineered biomarkers (from plant photoreceptors - phytochromes), providing high permeability of emission through biological tissues - miRFP670 (lem ~ 670nm ), miRFP703 (703 nm) and miRFP709 (709 nm), have been studied by X-ray method with resolution 1.33, 1.35 and 1.34Å, respectively. Three-dimensional structure and structure-functional relations of these biomarkers have been established
- (2017). Designing brighter near-infrared fluorescent proteins: Insights from structural and biochemical studies. Chem Sci 8 (6), 4546–4557
Deep structure-functional analysis of amino acid substitutions on photophysical properties of green fluorescent proteins
A so called “fitness landscape” was for the first time experimentally probed at the whole protein level using GFP as a model. A unique approach developed in this work enabled to correlate a function (fluorescence) with amino acid sequence of several tens of thousands of random mutants, revealing a number of negative and positive epistatic interactions between substitutions. Characterization of the GFP fitness landscape allows for computer prediction of properties of new mutants of fluorescent proteins. It also has important implications for several fields including molecular evolution and protein design.
Using calculations of the possible electron transfer pathways from excited GFP chromophore to external molecules and further experimental verification of these hypotheses, we constructed mutants with blocked electron transfer pathway and correspondingly increased photostability. This strategy may represent a new approach toward enhancing photostability of fluorescent proteins.
Figure. (A) Scheme of GFP fitness landscape derived from analysis of 51000 mutants. The GFP sequence arranged in a circle, each column representing one amino acid site. In the first circle, the colour intensity of the squares indicates the brightness of a single mutation at the corresponding site relative to the wild type, shown in the centre. Sites with positive and negative epistatic interactions between pairs of mutations are connected by green and black lines, respectively. In circles further away from the centre, representing genotypes with multiple mutations, the fraction of the column coloured green (black) represents the fraction of genotypes corresponding to high (low) fluorescence among all assayed genotypes with a mutation at that site. (B) Electron transfer in GFP. Upper panel – scheme of calculated pathway of electron transfer from the chromophore to external acceptor molecule via tyrosine-145 as an intermediate electron acceptor. Bottom panel – photobleaching curves of EGFP and its mutants in the presence of oxidant in the medium, showing a dramatic enhancement of photostability due to blocking the electron transfer pathway.
- (2016). Local fitness landscape of the green fluorescent protein. Nature 533 (7603), 397–401
- (2016). Turning on and off Photoinduced Electron Transfer in Fluorescent Proteins by π-Stacking, Halide Binding, and Tyr145 Mutations. J Am Chem Soc 138 (14), 4807–4817
- (2017). Photoinduced chemistry in fluorescent proteins: Curse or blessing? Chem Rev 117 (2), 758–795
A new phototoxic fluorescent biomarker with Trp-based chromophore
Three dimensional structure of two new phototoxic orange fluorescent proteins, dimeric KillerOrange and monomeric m KillerOrange, have been determined by X-ray method at resolution 1.81Å and 1.57 Å, respectively. They are first orange-emitting protein photosensitizers with a tryptophan-based chromophore (Gln65-Trp66-Gly67). The β-barrel structure of both orange photosensitizers has an internal channel extending along the β-barrel axis. It is filled with a chain of hydrogen-bonded water molecules providing an outlet for the photo-generated reactive oxygen spices. Trp66 of the chromophore in KillerOrange/mKillerOrange adopts an unusual high energy trans-cis conformation stabilized by H-bond with the nearby Gln159. The observed trans-cis isomer of Trp66 presents first example among those found in known Trp-based chromophores. This conformation was suggested a key structural feature for generation of bright orange emission and phototoxicity.
- (2015). Crystal structure of phototoxic orange fluorescent proteins with a tryptophan-based chromophore. PLoS One 10 (12), e0145740
Method for analysis of nonsense-mediated mRNA decay in the single live cells using fluorescent proteins
Nonsense-mediated mRNA decay (NMD) is an evolutionary conserved mechanism of recognition and degradation of transcripts with a premature stop-codon. Recent studies demonstrated that NMD plays an important role in global regulation of gene expression. We developed novel reporter of NMD activity based on fluorescent proteins. It enables quantitative analysis of NMD activity at the level of single live cells (this cannot be done by any other known method of NMD analysis). Using our NMD reporter, we revealed strong differences of NMD activity between mammalian cell lines. Also, a phenomenon of significant heterogeneity of NMD activity within some cell lines was observed for the first time. In particular, subpopulations of cells with high and low NMD activity were detected in HEK293, Jurkat, and HaCaT cells. Our method opens new possibilities to decipher mechanisms of NMD regulation as well as to study consequences of low NMD activity on gene expression patterns and cell physiology.
- (2015). Differences of Nonsense-Mediated mRNA Degradation Activity in Mammalian Cell Lines Revealed by a Fluorescence Reporter. Bioorg Khim 41 (5), 587–591
- (2015). Novel uses of fluorescent proteins. Curr Opin Chem Biol 27, 1–9
- (2015). Method for quantitative analysis of nonsense-mediated mRNA decay at the single cell level. Sci Rep 5, 7729