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Keane PM, Zehe C, Poynton FE, Bright SA, Estayalo-Adrián S, Devereux SJ, Donaldson PM, Sazanovich IV, Towrie M, Botchway SW, Cardin CJ, Williams DC, Gunnlaugsson T, Long C, Kelly JM, Quinn SJ. Time-resolved infra-red studies of photo-excited porphyrins in the presence of nucleic acids and in HeLa tumour cells: insights into binding site and electron transfer dynamics. Phys Chem Chem Phys 2022; 24:27524-27531. [PMID: 36345709 DOI: 10.1039/d2cp04604k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
Cationic porphyrins based on the 5,10,15,20-meso-(tetrakis-4-N-methylpyridyl) core (TMPyP4) have been studied extensively over many years due to their strong interactions with a variety of nucleic acid structures, and their potential use as photodynamic therapeutic agents and telomerase inhibitors. In this paper, the interactions of metal-free TMPyP4 and Pt(II)TMPyP4 with guanine-containing nucleic acids are studied for the first time using time-resolved infrared spectroscopy (TRIR). In D2O solution (where the metal-free form exists as D2TMPyP4) both compounds yielded similar TRIR spectra (between 1450-1750 cm-1) following pulsed laser excitation in their Soret B-absorption bands. Density functional theory calculations reveal that vibrations centred on the methylpyridinium groups are responsible for the dominant feature at ca. 1640 cm-1. TRIR spectra of D2TMPyP4 or PtTMPyP4 in the presence of guanosine 5'-monophosphate (GMP), double-stranded {d(GC)5}2 or {d(CGCAAATTTGCG)}2 contain negative-going signals, 'bleaches', indicative of binding close to guanine. TRIR signals for D2TMPyP4 or PtTMPyP bound to the quadruplex-forming cMYC sequence {d(TAGGGAGGG)}2T indicate that binding occurs on the stacked guanines. For D2TMPyP4 bound to guanine-containing systems, the TRIR signal at ca. 1640 cm-1 decays on the picosecond timescale, consistent with electron transfer from guanine to the singlet excited state of D2TMPyP4, although IR marker bands for the reduced porphyrin/oxidised guanine were not observed. When PtTMPyP is incorporated into HeLa tumour cells, TRIR studies show protein binding with time-dependent ps/ns changes in the amide absorptions demonstrating TRIR's potential for studying light-activated molecular processes not only with nucleic acids in solution but also in biological cells.
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Affiliation(s)
- Páraic M Keane
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.
- School of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, UK
| | - Clara Zehe
- School of Chemistry, University College Dublin, Dublin 4, Ireland.
| | - Fergus E Poynton
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.
- Trinity Biomedical Sciences Institute, The University of Dublin, Pearse St., Dublin 2, Ireland
| | - Sandra A Bright
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.
- Trinity Biomedical Sciences Institute, The University of Dublin, Pearse St., Dublin 2, Ireland
| | - Sandra Estayalo-Adrián
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.
- Trinity Biomedical Sciences Institute, The University of Dublin, Pearse St., Dublin 2, Ireland
| | | | - Paul M Donaldson
- STFC Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - Igor V Sazanovich
- STFC Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - Michael Towrie
- STFC Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - Stanley W Botchway
- STFC Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - Christine J Cardin
- School of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, UK
| | - D Clive Williams
- Trinity Biomedical Sciences Institute, The University of Dublin, Pearse St., Dublin 2, Ireland
| | - Thorfinnur Gunnlaugsson
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.
- Trinity Biomedical Sciences Institute, The University of Dublin, Pearse St., Dublin 2, Ireland
| | - Conor Long
- School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
| | - John M Kelly
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.
| | - Susan J Quinn
- School of Chemistry, University College Dublin, Dublin 4, Ireland.
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Wang LL, Yang YB, Cen JH, Lan J, Wang HH, Liu QC, Wu AB, Wang H, Liu HY. Fluorescence lifetime imaging of water-soluble porphyrin in human nasopharyngeal cells under two-photon excitation. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2022.114416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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