A study of metalloporphyrin-polynucleotide interactions by microcalorimetry and circular dichroism.
In this paper we examine the interactions of Calf Thymus DNA and the model polynucleotides poly(dA).poly(dT), poly(dAdT)2 and poly(dG.dC)2 with a group of metalloporphyrins derived from the freebase porphyrin tetrakis(4-N-methylpyridyl)porphine, H2(TMpy-P4), by means of ultraviolet absorption spectroscopy, circular dichroism spectroscopy and microcalorimetry. We have studied the interactions of the copper, cobalt, nickel and zinc derivatives of H2(TMpy-P4) in addition to the free base porphyrin itself. We have found strong evidence for an external self-stacking interaction of the Cu(TMpy-P4) and Zn(TMpy-P4) derivatives with poly(dA).poly(dT) and poly(dAdT)2 even at low concentrations of porphyrin, and all of the porphyrin derivatives studied appear to display such a self-stacking in interaction with poly(dA.dT)2 at sufficiently high ratios of porphyrin to polynucleotide.
Wheeler
G
G
LPBC, Université Paris VI, Paris, France.
Miskovsky
P
P
Jancura
D
D
Chinsky
L
L
D000818:Animals; D002151:Calorimetry / Q000379:methods*; D002417:Cattle; D002942:Circular Dichroism; D008665:Metalloporphyrins / Q000378:metabolism*; D011067:Poly dA-dT / Q000378:metabolism; D011089:Polydeoxyribonucleotides / Q000378:metabolism; D011119:Polynucleotides / Q000378:metabolism*
D008665:Metalloporphyrins; D011089:Polydeoxyribonucleotides; D011119:Polynucleotides; D011067:Poly dA-dT; C019530:poly(dC-dG)