Binding of new cationic porphyrin–tetrapeptide conjugates to nucleoprotein complexes

Orosz, Ádám and Mező, Gábor and Herényi, Levente and Habdas, Jan and Majer, Zsuzsa and Mysliwa-Kurdziel, Beata and Tóth, Katalin and Csík, Gabriella (2013) Binding of new cationic porphyrin–tetrapeptide conjugates to nucleoprotein complexes. Biophysical Chemistry, 177. pp. 14-23. ISSN 0301-4622

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Ongoing research on DNA binding of cationic porphyrin derivatives and their conjugates is a subject of growing interest because of their possible DNA binding and demonstrated biological properties. In this study nucleo-protein binding of tri-cationic meso-tri(4-N-methylpyridyl)-mono-(4-carboxyphenyl)porphyrin (TMPCP) and tetrapeptides conjugated TMPCP (TMPCP-4P) and bi-cationic meso-5,10-bis(4-N-methylpyridyl)-15,20-di-(4-carboxyphenyl)porphyrin (BMPCP-4P2) was investigated with comprehensive spectroscopic methods. The key observation is that tetrapeptide-conjugates of cationic porphyrins with two or three positive charges bind to encapsidated DNA in T7 phage nucleoprotein complex. The binding modes were analyzed byfluorescent en-ergy transfer,fluorescent life time and CD measurements. Intercalative binding ismost feasiblewhen tricationic ligands complex withDNA, especiallywhen it is in close connection with protein capsid. It was found that larger ligand BMPCP-4P2binds externally to encapsidated T7 DNA, and complex externally as well as by intercalation when the DNA accommodate to relaxed B-conformation. In the case of TMPCP and TMPCP-4P the intercalation is the predominant binding form both in nucleoprotein (NP) and preheated complexes. Further, meltingexperiments revealed that bound porphyrins do not influence the capsid stability or protein–DNA interactions, but efficiently stabilize the double helical structure of DNA without respect to binding form. A good correlation was found between porphyrin/base pair ration and DNA strand separation temperature.

Item Type: Article
Uncontrolled Keywords: Cationic porphyrin Porphyrin–peptide conjugate Fluorescence spectroscopy Induced ECD-signal Absorption melting Nucleoprotein–porphyrin binding
Subjects: Q Science / természettudomány > QD Chemistry / kémia > QD04 Organic chemistry / szerves kémia
R Medicine / orvostudomány > R1 Medicine (General) / orvostudomány általában
Depositing User: Dr Katalin Uray
Date Deposited: 04 Feb 2014 12:42
Last Modified: 04 Feb 2014 12:48

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