Abstract and References
Transactions on Science and Technology Vol. 4, No. 3-3, 342 - 347, 2017

Monitoring and Optimizing the Lipopolysaccharides-plasmid DNA interaction by FLIM-FRET

Nur Syahadatain Abdul Razak, Clarence M. Ongkudon, Sudhaharan Thankiah
ABSTRACT
 In this work, in vitro FLIM-FRET experiments were performed to measure the interaction of divalent metal cations such as Zn2+ and Mg2+ with lipopolysaccharides (LPS) and plasmid DNA (pDNA). For Zn2+ induced interaction with LPS-DNA, the fluorescence lifetime of donor (Alexa Fluor 488 conjugate LPS) was 3.97 ns. Once acceptor (Alexa Fluor 594-labeled pDNA) was added, a sharp decrease in lifetime of 3.16 ns was observed. FRET efficiency for the interaction was calculated based on the change in fluorescence lifetime. The 20 % FRET efficiency calculated suggesting that significant interaction occurred. While for the interaction with Mg2+, donor lifetime alone was 3.72 ns. After the addition of acceptor, a slight decrease in lifetime was detected, 3.66 ns, corresponding to a low FRET efficiency of 1.6 % was recorded reflecting a very weak interaction. Data from FLIM images also showed that Zn2+ induced higher degree of aggregation compared to Mg2+. As part of the ongoing research project, the selectivity of Zn2+ over pDNA/ LPS and its ability to enhance aggregation are yet to be investigated.

KEYWORDS: In vitro; lipopolysaccharides; Forster Resonance Energy Transfer; Fluorescence Lifetime Imaging Microscopy; divalent metal cations

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