Effect of introducing thymine spacers into an adenine strand : Electronic decoupling?

• Electronic coupling between DNA bases governs the deexcitation pathways after light absorption as well as the ability of the DNA strand to conduct charge. UV excitation of single strands of adenine bases involves two adjacent bases while the spatial extent of the excited state wavefunction following VUV excitation is over eight bases. In this work, we have recorded synchrotron radiation circular dichroism spectra for a series of DNA strands on the form A(n)T(m)A(n), n = 1-5 and m = 1-3, in aqueous solution to study the effect of introducing thymine spacers on the electronic coupling between the adenines. We find that a single thymine spacer is enough to eliminate the strong coupling between the adenine bases for all excitation wavelengths between 175 nm and 330 nm.

Ämnesord

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Nyckelord

DNA strands

Synchrotron radiation

Circular dichroism

Electronic coupling

Adenine bases

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