Issue 8, 2016

Ground and excited state interactions of metalloporphyrin PtTMPyP4 with polynucleotides [poly(dG-dC)]2 and [poly(dA-dT)]2

Abstract

The ground- and excited-state interactions of Pt(II) meso-tetrakis(4-N-methylpyridyl)porphyrin (PtTMPyP4) with polynucleotides [poly(dG-dC)]2 and [poly(dA-dT)]2 have been investigated using UV/visible, circular dichroism, and steady-state and time-resolved emission spectroscopy. PtTMPyP4 intercalates into [poly(dG-dC)]2 with K ∼ 106 M−1. When bound to [poly(dG-dC)]2 in aerated solution there is a six-fold emission enhancement with 18 nm red-shift in emission maximum. Emission lifetimes are biexponential. In the presence of [poly(dA-dT)]2 at least two distinct groove-binding modes are observed, depending on the binding ratio. In [poly(dA-dT)]2 the emission intensity increases by a maximum factor of 17 with no shift in the emission spectrum. Three exponentials were required for lifetime fitting. The lower extent of emission enhancement in the presence of [poly(dG-dC)]2 suggests that a slow electron transfer may take place to guanine, which is significantly less efficient than that previously observed for PtTMPyP4 in the presence of guanosine 5′-monophosphate (GMP). The results are compared to those previously recorded with free base H2TMPyP4.

Graphical abstract: Ground and excited state interactions of metalloporphyrin PtTMPyP4 with polynucleotides [poly(dG-dC)]2 and [poly(dA-dT)]2

Supplementary files

Article information

Article type
Paper
Submitted
12 Apr 2016
Accepted
23 Jun 2016
First published
27 Jun 2016

Photochem. Photobiol. Sci., 2016,15, 980-987

Author version available

Ground and excited state interactions of metalloporphyrin PtTMPyP4 with polynucleotides [poly(dG-dC)]2 and [poly(dA-dT)]2

P. M. Keane and J. M. Kelly, Photochem. Photobiol. Sci., 2016, 15, 980 DOI: 10.1039/C6PP00105J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Spotlight

Advertisements