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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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Devereux SJ, Massaro M, Barker A, Hinds DT, Hifni B, Simpson JC, Quinn SJ. Spectroscopic study of the loading of cationic porphyrins by carbon nanohorns as high capacity carriers of photoactive molecules to cells. J Mater Chem B 2019. [DOI: 10.1039/c9tb00217k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Spherical carbon nanohorns have great potential as drug delivery agents. Here a detailed study of the loading of porphyrin molecules is reported and the influence on their stability described. An optimally loaded sample is shown to cause photoactivated cell death.
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Affiliation(s)
| | - Marina Massaro
- School of Chemistry
- University College Dublin
- Dublin 4
- Ireland
| | - Andrew Barker
- School of Chemistry
- University College Dublin
- Dublin 4
- Ireland
| | - David T. Hinds
- School of Chemistry
- University College Dublin
- Dublin 4
- Ireland
| | - Badriah Hifni
- School of Chemistry
- University College Dublin
- Dublin 4
- Ireland
- School of Biology & Environmental Science, University College Dublin, Belfield
| | - Jeremy C. Simpson
- School of Biology & Environmental Science, University College Dublin, Belfield
- Dublin 4
- Ireland
| | - Susan J. Quinn
- School of Chemistry
- University College Dublin
- Dublin 4
- Ireland
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