Role of secondary structure and time-dependent binding on disruption of phthalocyanine aggregates by guanine-rich nucleic acids

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Windle, Eleanor R. and Rennie, Christopher C. and Edkins, Robert M. and Quinn, Susan J. (2024) Role of secondary structure and time-dependent binding on disruption of phthalocyanine aggregates by guanine-rich nucleic acids. Chemistry - A European Journal. e202403095. ISSN 1521-3765 (https://doi.org/10.1002/chem.202403095)

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Abstract

Phthalocyanines are versatile photodynamic therapy agents whose biological activity depends on their aggregation state, which is expected to be influenced by binding to biomolecules. Here, guanine-rich nucleic acid binding of a water-soluble cationic, regiopure C4h zinc phthalocyanine bearing four triethylene glycol methyl ether and four N-methyl-4-pyridinium substituents (1) is reported. In contrast to double-stranded DNA, guanine systems GpG, (GG)10, poly(G) and quadruplex DNA are shown to effectively disrupt phthalocyanine aggregates in buffered solution. This process is accompanied by evolution of the Q-band absorbance and enhanced emission. Increasing the sequence length from GpG to (GG)10 increases the binding and confirms the importance of multiple binding interactions. Enhanced binding in the presence of KCl suggests the importance of nucleobase hydrogen-bonded mosaics in phthalocyanine binding. Notably, the (GT)10 sequence is even more effective than quadruplex and pure guanine systems at disrupting the aggregates of 1. Significant time-dependent binding of 1 with poly(G) reveals biexponential binding over minutes and hours, which is linked to local conformations of poly(G) that accommodate monomers of 1 over time. The study highlights the ability of biomacromolecules to disrupt phthalocyanines aggregates over time, which is an important consideration when rationalizing photoactivity of photosensitizers in-vivo.

ORCID iDs

Windle, Eleanor R., Rennie, Christopher C., Edkins, Robert M. ORCID logoORCID: https://orcid.org/0000-0001-6117-5275 and Quinn, Susan J.;
  • Item type:Article
    ID code:91568
    Dates:
    Date
    Event
    29 November 2024
    Published
    29 November 2024
    Published Online
    28 November 2024
    Accepted
    16 August 2024
    Submitted
    Subjects:Science > Chemistry
    Department:Faculty of Science > Pure and Applied Chemistry
    Depositing user: Pure Administrator
    Date deposited:12 Dec 2024 17:30
    Last modified:18 Dec 2024 01:43
    URI:https://strathprints.strath.ac.uk/id/eprint/91568
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