N-Methyl Mesoporphorin IX, A Reporter On GQ-DNA, Forms A Dimer In Aqueous Solution

Document Type

Poster Session

Publication Date

2-8-2024

Published In

Biophysical Journal

Abstract

N-methyl mesoporphyrin IX (NMM) has rapidly become a significant tool for the characterization of quadruplex DNA (GQ-DNA) structures. These novel DNA structures are of interest due to their enrichment in protooncogene sequences and telomeres [Kosiol 2021]. As NMM becomes a standard tool in the sub-field of GQ-DNA research, it becomes increasingly important to understand its behavior. NMM's utility is based on a shift in absorbance from a max at 379 nm to a max at 400 nm in the presence of GQ binding partners, and fluorescence enhancement upon the presence of binding partners [Yett 2019]. In this work we present data showing that NMM, in aqueous solution, without GQ-DNA present, shows a concentration dependent shift in peak absorbance from 400 nm to 379 nm with increasing concentration. Analysis, using singular value decomposition (SVD), shows that this shift is consistent with NMM forming a dimer. In addition, NMM displays increasing fluorescence intensity with increasing temperature, consistent with fluorescence quenching in the dimer state. These data suggest that some of the attributes of NMM as a GQ-DNA probe may be due to the presence of GQ-DNA, and associated binding, changing the effective concentration of free NMM in solution.

Conference

Biophysical Society Annual Meeting 2024

Conference Dates

February 10-14, 2024

Conference Location

Philadelphia, PA

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