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Marton Menendez A, Nesbitt DJ. Ionic Cooperativity between Lysine and Potassium in the Lysine Riboswitch: Single-Molecule Kinetic and Thermodynamic Studies. J Phys Chem B 2023; 127:2430-2440. [PMID: 36916791 DOI: 10.1021/acs.jpcb.3c00245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Functionality in many biological systems, including proteins and nucleic acid structures, including protein and nucleic acid riboswitch structures, can depend on cooperative kinetic behavior between multiple small molecule ligands. In this work, single-molecule FRET data on the Bacillus subtilis lysine riboswitch reveals that affinity for the cognate lysine ligand increases significantly with K+, providing evidence for synergism between lysine/K+ binding to the aptamer and successful folding of the riboswitch. To describe/interpret this more complex kinetic scenario, we explore the conventional 4-state ("square") model for aptamer binding as a function of K+. Extension into this additional dimension generates a novel "cube" model for riboswitch folding dynamics with respect to lysine/K+ binding, revealing that riboswitch folding (kfold) and unfolding (kunfold) rate constants increase and decrease dramatically with K+, respectively. Furthermore, temperature-dependent single-molecule kinetic studies indicate that the presence of K+ entropically enhances the transition state barrier to folding but partially compensates for this by increasing the overall exothermicity for lysine binding. We rationalize this behavior as evidence that K+ facilitates hydrogen bonding between the negatively charged carboxyl group of lysine and the RNA, increasing structural rigidity and lowering entropy in the binding pocket. Finally, we explore the effects of cation size with Na+ and Cs+ studies to demonstrate that K+ is optimally suited for bridging interactions between lysine and the riboswitch aptamer domain. Regulation of lysine production and transport, dictated by the riboswitch's ability to recognize and bind lysine, is therefore intimately tied to the presence of K+ in the binding pocket and is strongly modulated by local cation conditions. The results suggest an increase in lysine riboswitch functionality by sensitivity to additional species in the cellular riboswitch environment.
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Affiliation(s)
- Andrea Marton Menendez
- JILA, University of Colorado Boulder and National Institute of Standards and Technology, Boulder, Colorado 80309, United States
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - David J Nesbitt
- JILA, University of Colorado Boulder and National Institute of Standards and Technology, Boulder, Colorado 80309, United States
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309, United States
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Skelton E, Erasquin U, Sukul A, Zuercher A, White J, Bythell BJ, Cimatu KLA. Visible Light-Assisted Coordination of a Rh(III)-BODIPY Complex to Guanine. Inorg Chem 2023; 62:3368-3380. [PMID: 36795094 DOI: 10.1021/acs.inorgchem.2c03289] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Most photodynamic therapeutics (PDTs) used in cancer treatment require oxygen to work efficiently to terminate cancer cells. These PDTs do not efficiently treat tumors in hypoxic conditions. Rh(III) polypyridyl complexes have been reported to have a photodynamic therapeutic effect in hypoxic conditions when exposed to UV light. UV light can damage tissue and cannot penetrate deep to reach cancer cells. This work proposes the coordination of a BODIPY fluorophore to a rhodium metal center to form a Rh(III)-BODIPY complex that enhances the reactivity of the rhodium under visible light. This complex formation is facilitated with the BODIPY as the highest occupied molecular orbital (HOMO), while the lowest unoccupied molecular orbital (LUMO) is localized on the Rh(III) metal center. Irradiation of the BODIPY transition at ∼524 nm can cause an indirect electron transfer from the orbital of the BODIPY-centered HOMO to the Rh(III)-centered LUMO, populating the dσ* orbital. In addition, photo binding of the Rh complex covalently coordinated to the N (7) position of guanine in an aqueous solution was also observed by mass spectrometry after chloride dissociation upon irradiation with green visible light (532 nm LED). Calculated thermochemistry values of the Rh complex reaction in methanol, acetonitrile, water, and guanine were determined using DFT calculations. All enthalpic reactions and Gibbs free energies were identified as endothermic and nonspontaneous, respectively. This observation supports the chloride dissociation using 532 nm light. This Rh(III)-BODIPY complex expands the class of visible light-activated Rh(III) photocisplatin analogs that may have potential photodynamic therapeutic activity for the treatment of cancers in hypoxic conditions.
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Affiliation(s)
- Eli Skelton
- College of Arts and Sciences, Department of Chemistry and Biochemistry, 133 University Terrace, Chemistry Building Ohio University, Athens, Ohio 45701, United States
| | - Uriel Erasquin
- College of Arts and Sciences, Department of Chemistry and Biochemistry, 133 University Terrace, Chemistry Building Ohio University, Athens, Ohio 45701, United States
| | - Abhijit Sukul
- College of Arts and Sciences, Department of Chemistry and Biochemistry, 133 University Terrace, Chemistry Building Ohio University, Athens, Ohio 45701, United States
| | - Aoife Zuercher
- College of Arts and Sciences, Department of Chemistry and Biochemistry, 133 University Terrace, Chemistry Building Ohio University, Athens, Ohio 45701, United States
| | - Jessica White
- College of Arts and Sciences, Department of Chemistry and Biochemistry, 133 University Terrace, Chemistry Building Ohio University, Athens, Ohio 45701, United States
| | - Benjamin J Bythell
- College of Arts and Sciences, Department of Chemistry and Biochemistry, 133 University Terrace, Chemistry Building Ohio University, Athens, Ohio 45701, United States
| | - Katherine Leslee Asetre Cimatu
- College of Arts and Sciences, Department of Chemistry and Biochemistry, 133 University Terrace, Chemistry Building Ohio University, Athens, Ohio 45701, United States
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Coleman BD, d'Aquino AI, Kean Z, Wang Y, Hedlund Orbeck JK, Stern CL, Mirkin CA. Structurally Dynamic Crystalline 1D Coordination Polymers Enabled via the Weak-Link Approach. Polyhedron 2022. [DOI: 10.1016/j.poly.2022.116116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Mandal T, Singh V, Choudhury J. Coordination Booster-Catalyst Assembly: Remote Osmium Outperforming Ruthenium in Boosting Catalytic Activity. Chem Asian J 2019; 14:4774-4779. [PMID: 31560812 DOI: 10.1002/asia.201901215] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 09/26/2019] [Indexed: 12/15/2022]
Abstract
Presented herein is a set of bimetallic and trimetallic "coordination booster-catalyst" assemblies in which the coordination complexes [RuII (terpy)2 ] and [OsII (terpy)2 ] acted as boosters for enhancement of the catalytic activity of [RuII (NHC)(para-cymene)]-based catalytic site. The boosters accelerated the oxidative loss of para-cymene from the catalytic site to generate the active catalyst during the oxidation of alkenes and alkynes into corresponding aldehydes, ketones and diketones. It was found that the boosting efficiency of the [OsII (terpy)2 ] units was considerably higher than its congener [RuII (terpy)2 ] unit in these assemblies. Mechanistic studies were conducted to understand this unique improvement.
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Affiliation(s)
- Tanmoy Mandal
- Organometallics & Smart Materials Laboratory, Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal, 462 066, India
| | - Vivek Singh
- Organometallics & Smart Materials Laboratory, Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal, 462 066, India
| | - Joyanta Choudhury
- Organometallics & Smart Materials Laboratory, Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal, 462 066, India
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Lu Z, Lavendomme R, Burghaus O, Nitschke JR. A Zn
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Capsule with Enhanced Catalytic C−C Bond Formation Activity upon C
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Binding. Angew Chem Int Ed Engl 2019; 58:9073-9077. [DOI: 10.1002/anie.201903286] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 04/20/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Zhenpin Lu
- Department of ChemistryUniversity of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Roy Lavendomme
- Department of ChemistryUniversity of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Olaf Burghaus
- Fachbereich ChemiePhilipps-Universität Marburg Hans-Meerwein-Str. 4 35032 Marburg Germany
| | - Jonathan R. Nitschke
- Department of ChemistryUniversity of Cambridge Lensfield Road Cambridge CB2 1EW UK
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Lu Z, Lavendomme R, Burghaus O, Nitschke JR. A Zn
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Capsule with Enhanced Catalytic C−C Bond Formation Activity upon C
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Binding. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201903286] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Zhenpin Lu
- Department of ChemistryUniversity of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Roy Lavendomme
- Department of ChemistryUniversity of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Olaf Burghaus
- Fachbereich ChemiePhilipps-Universität Marburg Hans-Meerwein-Str. 4 35032 Marburg Germany
| | - Jonathan R. Nitschke
- Department of ChemistryUniversity of Cambridge Lensfield Road Cambridge CB2 1EW UK
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Parks FC, Liu Y, Debnath S, Stutsman SR, Raghavachari K, Flood AH. Allosteric Control of Photofoldamers for Selecting between Anion Regulation and Double-to-Single Helix Switching. J Am Chem Soc 2018; 140:17711-17723. [DOI: 10.1021/jacs.8b10538] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Fred C. Parks
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Yun Liu
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Sibali Debnath
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Sydney R. Stutsman
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Krishnan Raghavachari
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Amar H. Flood
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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Liu Y, Zhou J, Wasielewski MR, Xing H, Mirkin CA. A four-state fluorescent molecular switch. Chem Commun (Camb) 2018; 54:12041-12044. [PMID: 30294737 PMCID: PMC6203447 DOI: 10.1039/c8cc05159c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Four distinct fluorescent states are achieved in a single Weak-Link Approach (WLA) construct bearing pyrene and tetraphenylethene moieties. The fluorescence of the compound in both the solution and solid phases can be manipulated through reversible coordination chemistry at the PtII center.
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Affiliation(s)
- Yuan Liu
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA. ;
| | - Jiawang Zhou
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA. ;
- Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208, USA
| | - Michael R. Wasielewski
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA. ;
- Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208, USA
| | - Hang Xing
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA. ;
- Institute of Chemical Biology and Nanomedicine, Molecular Science and Biomedicine Laboratory, State Key Laboratory for Chemo/Bio Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, China
| | - Chad A. Mirkin
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA. ;
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Andrews MC, Peng P, Rajput A, Cozzolino AF. Modulation of the carboxamidine redox potential through photoinduced spiropyran or fulgimide isomerisation. Photochem Photobiol Sci 2018. [PMID: 29528073 DOI: 10.1039/c7pp00347a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Carboxamidines functionalized with either a spiropyran or fulgimide photoswitch were prepared on multigram scales. The thermal, electrochemical, and photochemical ring isomerizations of these compounds were studied and the results compared with related systems. The photochemical isomerisations were found to be reversible and could be followed by 1H NMR and UV-vis spectroscopy. The spiropyran/merocyanine couple was thermally active and an activation enthalpy of 116 kJ mol-1 was measured for ring-opening. These measurements yielded an enthalpy difference of 25 kJ mol-1 between the open and closed states which is consistent with DFT calculations. DFT calculations predicted a charge transfer to the carboxamidine group upon ring closure in the fulgimide and a charge transfer from the carboxamidine group upon switching the spiropyran to the merocyanine form. This was confirmed experimentally by monitoring the change in the oxidation potential assigned to the carboxamidine group. The potential of these molecules to therefore act as a new class of photoresponsive ligands that can modulate the ligand field of a complex is discussed.
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Affiliation(s)
- M Crawford Andrews
- Department of Chemistry and Biochemistry, Texas Tech University, MS 41061, Lubbock, TX 79409, USA.
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Lei H, Karsenti PL, Harvey PD. Azophenine as Central Core for Efficient Light Harvesting Devices. Chemphyschem 2018; 19:596-611. [PMID: 29205732 DOI: 10.1002/cphc.201701183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/02/2017] [Indexed: 01/12/2023]
Abstract
The notoriously non-luminescent uncycled azophenine (Q) was harnessed with Bodipy and zinc(II)porphyrin antennas to probe its fluorescence properties, its ability to act as a singlet excited state energy acceptor and to mediate the transfer. Two near-IR emissions are depicted from time-resolved fluorescence spectroscopy, which are most likely due to the presence of tautomers of very similar calculated total energies (350 cm-1 ; DFT; B3LYP). The rates for energy transfer, kET (S1 ), for 1 Bodipy*→Q are in the order of 1010 -1011 s-1 and are surprisingly fast when considering the low absorptivity properties of the lowest energy charge transfer excited state of azophenine. The rational is provided by the calculated frontier molecular orbitals (MOs) which show atomic contributions in the C6 H4 C≡CC6 H4 arms, thus favoring the double electron exchange mechanism. In the mixed-antenna Bodipy-porphyrin star molecule, the rate for 1 Bodipy*→porphyrin has also been evaluated (≈16×1010 s-1 ) and is among the fastest rates reported for Bodipy-zinc(II)porphyrin pairs. This astonishing result is again explained from the atomic contributions of the C6 H4 C≡CC6 H4 and C≡CC6 H4 arms thus favouring the Dexter process. Here, for the first time, this process is found to be sensitively temperature-dependent. The azophenine turns out to be excellent for electronic communication.
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Affiliation(s)
- Hu Lei
- Département de chimie, Université de Sherbrooke, PQ, J1K 2R1, Canada
| | | | - Pierre D Harvey
- Département de chimie, Université de Sherbrooke, PQ, J1K 2R1, Canada
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Liu Y, Kean ZS, d’Aquino AI, Manraj YD, Mendez-Arroyo J, Mirkin CA. Palladium(II) Weak-Link Approach Complexes Bearing Hemilabile N-Heterocyclic Carbene–Thioether Ligands. Inorg Chem 2017; 56:5902-5910. [PMID: 28471640 DOI: 10.1021/acs.inorgchem.7b00543] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Yuan Liu
- Department of Chemistry and International
Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Zachary S. Kean
- Department of Chemistry and International
Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Andrea I. d’Aquino
- Department of Chemistry and International
Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Yashin D. Manraj
- Department of Chemistry and International
Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Jose Mendez-Arroyo
- Department of Chemistry and International
Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Chad. A. Mirkin
- Department of Chemistry and International
Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
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