title: Coordination to Imidazole Ring Switches on Phosphorescence of Platinum Cyclometalated Complexes: The Route to Selective Labeling of Peptides and Proteins via Histidine Residues.
abstract: In this study, we have shown that substitution of chloride ligand for imidazole (Im) ring in the cyclometalated platinum complex Pt(phpy)(PPh3)Cl (1; phpy, 2-phenylpyridine; PPh3, triphenylphosphine), which is nonemissive in solution, switches on phosphorescence of the resulting compound. Crystallographic and nuclear magnetic resonance (NMR) spectroscopic studies of the substitution product showed that the luminescence ignition is a result of Im coordination to give the [Pt(phpy)(Im)(PPh3)]Cl complex. The other imidazole-containing biomolecules, such as histidine and histidine-containing peptides and proteins, also trigger luminescence of the substitution products. The complex 1 proved to be highly selective toward the imidazole ring coordination that allows site-specific labeling of peptides and proteins with 1 using the route, which is orthogonal to the common bioconjugation schemes via lysine, aspartic and glutamic acids, or cysteine and does not require any preliminary modification of a biomolecule. The utility of this approach was demonstrated on (i) site-specific modification of the ubiquitin, a small protein that contains only one His residue in its sequence, and (ii) preparation of nonaggregated HSA-based Pt phosphorescent probe. The latter particles easily internalize into the live HeLa cells and display a high potential for live-cell phosphorescence lifetime imaging (PLIM) as well as for advanced correlation PLIM and FLIM experiments.
authors.affiliation: Saint Petersburg State University , Institute of Chemistry, Universitetskii prospect. 26, 198504 Saint Petersburg, Russia.
authors.forename: Anastasia I
authors.initials: AI
authors.lastname: Solomatina
authors.affiliation: Saint Petersburg State University , Institute of Chemistry, Universitetskii prospect. 26, 198504 Saint Petersburg, Russia.|Institute of Macromolecular Compounds, Russian Academy of Sciences , Bolshoi prospect, Vasilievskii Island, 31, 199004 Saint Petersburg, Russia.
authors.forename: Pavel S
authors.identifier: 0000-0001-8922-506X
authors.initials: PS
authors.lastname: Chelushkin
authors.affiliation: Saint Petersburg State University , Institute of Chemistry, Universitetskii prospect. 26, 198504 Saint Petersburg, Russia.
authors.forename: Dmitrii V
authors.identifier: 0000-0002-5098-4541
authors.initials: DV
authors.lastname: Krupenya
authors.affiliation: Saint Petersburg State University , Biomolecular NMR Laboratory, Botanicheskaya Str., 17, 198504 Saint Petersburg, Russia.
authors.forename: Ivan S
authors.initials: IS
authors.lastname: Podkorytov
authors.affiliation: Research Center of Nanobiotechnologies, Peter the Great Saint Petersburg Polytechnic University , Polytechnicheskaya, 29, 195251 Saint Petersburg, Russia.
authors.forename: Tatiana O
authors.initials: TO
authors.lastname: Artamonova
authors.affiliation: Saint Petersburg State University , Institute of Chemistry, Universitetskii prospect. 26, 198504 Saint Petersburg, Russia.
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Sizov
authors.affiliation: Saint Petersburg State University , Department of Physics, Ulianovskaya Str., 3, 198504 Saint Petersburg, Russia.|Research Center of Nanobiotechnologies, Peter the Great Saint Petersburg Polytechnic University , Polytechnicheskaya, 29, 195251 Saint Petersburg, Russia.
authors.forename: Alexei S
authors.initials: AS
authors.lastname: Melnikov
authors.affiliation: Saint Petersburg State University , Institute of Earth Sciences and Biology Department, University embankment. 7/9, 199034 Saint Petersburg, Russia.
authors.forename: Vladislav V
authors.initials: VV
authors.lastname: Gurzhiy
authors.affiliation: Saint Petersburg State University , Institute of Earth Sciences and Biology Department, University embankment. 7/9, 199034 Saint Petersburg, Russia.
authors.forename: Elena I
authors.initials: EI
authors.lastname: Koshel
authors.affiliation: Becker & Hickl GmbH , Nahmitzer Damm 30, 12277 Berlin, Germany.
authors.forename: Vladislav I
authors.initials: VI
authors.lastname: Shcheslavskiy
authors.affiliation: Saint Petersburg State University , Institute of Chemistry, Universitetskii prospect. 26, 198504 Saint Petersburg, Russia.
authors.forename: Sergey P
authors.identifier: 0000-0002-9431-0944
authors.initials: SP
authors.lastname: Tunik
mesh_terms: D000595:Amino Acid Sequence; D006367:HeLa Cells; D006639:Histidine / Q000737:chemistry*; D006801:Humans; D007093:Imidazoles / Q000737:chemistry*; D008163:Luminescent Measurements; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*; D011487:Protein Conformation; D013194:Staining and Labeling; D025801:Ubiquitin / Q000737:chemistry*
chemical_list: D007093:Imidazoles; D009942:Organometallic Compounds; D010455:Peptides; D025801:Ubiquitin; D010984:Platinum; D006639:Histidine