Supramolecular helical porphyrin arrays using DNA as a scaffold

Nucleotides and Nucleic Acids; Oligo- and Polynucleotides

“…198 C5-Alkynylated pyrimidines have been coupled with various azides to generate fluorescent analogues, where they have been shown to be destabilising when paired with either an abasic site or the canonical base, 199 to a redox-active phenoxazine, 200 as a probe for photochemical ligation, 201 with azido-modified nucleotides to generate interstrand crosslinks 202 and to azido-modified gold particles. 203 Other alkynylated pyrimidine analogues involve propargylamine for use in triplexforming oligonucleotides, 204 attachment of oligothiophene 205 or anthracene 206 for use in detection of SNPs, attachment of a porphyrin, 207 incorporation of a spin label 208 and for the incorporation of fluorinated derivative (44) as a sensitive 19 F NMR probe. 209 Pyrimidines undergo a photochemical dimerisation to give mainly three different products, the cyclobutane dimer (CPD) (45), a pyrimidine (6-4 0 )-pyrimidone adduct (46) and the spore photoanalogue (47).…”

“…When several such modifications are incorporated into a ssDNA, the oligonucleotide shows a helical conformation, and when paired with its complementary strand it is fluorescent. 207 When a single porphyrin unit was conjugated into the backbone of a DNA duplex it formed a dimer, with stabilisation coming from stacking of the two porphyrin moieties. 513 A porphyrin has been attached to a 5 0 -aminomodified oligonucleotides, which was then spontaneously metallated in the presence of either Zn(II) or Cu(II) ions.…”

Synthesis of β‐Pyrrolic‐Modified Porphyrins and Their Incorporation into DNA

“…[12][13][14][15][16]21] The internal modification of ONs with porphyrins has recently become of interest for the development of helical scaffolds. Such examples include the synthesis of a DNA containing 11 meso-functionalised porphyrins on a single strand [5,6] and a zipper porphyrin assembly in the major groove of a DNA duplex. [7] In contrast to the common functionalisation of a porphyrin at the meso position, [5-9, 11, 20] which results in a system nearly orthogonal to the porphyrin core, we have recently synthesised a b-pyrrolic-modified porphyrin and shown that its H-aggregate formation in the minor groove significantly stabilised duplexes (DT m per modification = + + 7.5-7.9 8C).…”

“…[22] Duplex thermal stability exceeded 90 8C when four porphy-A C H T U N G T R E N N U N G rins were stacked in the zipper motif as a result of superior interactions between b-pyrrolic-modified porphyrins in comparison with previously studied DNA-porphyrin constructs. [5][6][7][8]17] We were curious, therefore, as to the effect of different attachments of b-pyrrolic porphyrin to DNA on Abstract: A synthetic methodology for the synthesis of various b-pyrrolic-functionalised porphyrins and their covalent attachment to 2'-deoxyuridine and DNA is described. Palladium(0)-catalysed Sonogashira and copper(I)-catalysed Huisgen 1,3-dipolar cycloaddition reactions were used to insert porphy-A C H T U N G T R E N N U N G rins into the structure of 2'-deoxyuridine and DNA.…”

“…[3] The site-specific covalent attachment of porphyrin moieties to DNA has been achieved by using a variety of methodologies including the modification of nucleobases, [4][5][6][7][8][9] ribofuranose residues, [10][11][12][13][14][15] the phosphate backbone [16,17] and acyclic linkers. [18,19] Porphyrin moieties have been introduced as 3'-or 5'-molecular caps, [13,[19][20][21] as a nucleobase substituent in the middle of the helix [18] or as a label in the minor [11,17,22] and major [5][6][7][8][9] grooves. Several tethers have been used for the covalent attachment of porphyrins including maleimidothiols, [8,17] amides, [11][12][13]15] phosphates [16] and alkynes.…”