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Introducing Structural Flexibility Into Porphyrin-DNA Zipper Arrays

DOI: 10.1039/c0ob00535e DOI Help

Authors: Eugen Stulz (University of Southampton) , Ashley Brewer (University of Southampton) , Guiliano Siligardi (Diamond Light Source) , Cameron Neylon (CCLRC)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Organic & Biomolecular Chemistry , VOL 9 , PAGES 777-782

State: Published (Approved)
Published: March 2011
Diamond Proposal Number(s): 1815

Abstract: A more flexible nucleotide building block for the synthesis of new DNA based porphyrin–zipper arrays is described. Changing the rigid acetylene linker between the porphyrin substituent and the 2′-deoxyuridine to a more flexible propargyl amide containing linkage leads in part to an increased duplex stability. The CD spectra reveal different electronic interactions between the porphyrins depending on the type of linker used. Molecular modelling suggests large variation of the relative orientation of the porphyrins within the major groove of the DNA. The porphyrins can be metallated post-synthetically with different metals as shown with zinc, cobalt and copper. The spectroscopic features do not alter drastically upon metallation apart from the CD spectra, and the stability of the metal complex is highly dependent on the nature of the metal. As shown by CD spectroscopy, the zinc porphyrin is rapidly demetallated at high temperatures. Globular structure determination using SAXS indicates that a molecular assembly comprised of a two to four helical bundle dominates in solution at higher concentrations (≥50 μM) which is not observed by spectroscopy at lower concentrations (≤1 μM).

Subject Areas: Chemistry, Biology and Bio-materials

Instruments: B23-Circular Dichroism