Photochemical consequences of porphyrin and phthalocyanine aggregation on nucleoprotein histone

Novel Heterotopic Colloids of Anionic Porphyrins Entangled in Cationic Amphiphilic Cyclodextrins: Spectroscopic Investigation and Intracellular Delivery

“…[28] Furthermore, literature data show a strong binding between TPPS and histones, positively charged nucleoproteins which play a key role in the compaction of chromatin in the nucleus. [29] Therefore, our findings point to the possibility that TPPS binds to the chromatin of the target cells. Further experiments will verify this possibility and clarify the significance of our observation.…”

Exciton relaxation in nanotubular TPPS4 aggregates in water solution and in polymeric matrix

“…The most likely candidates are triplet states, some exciton traps, photoproducts and charge transfer states. No triplet state formation was observed for aggregated TPPS 4 molecules [33], therefore their formation in our samples with 30% yield is hardly possible. The nonradiative exciton traps would have absorption and consequently transient absorption spectra different from those of dominating aggregate structures, therefore they would cause different transient absorption spectrum.…”

An Isothermal Titration Microcalorimetric Study on the Interaction of Three Water-Soluble Porphyrins with Histone H₂B

“…Previous study shows that histone promotes aggregation of the bound monomeric porphyrin. 19 Hence, for analyzing the enthalpy curves for obtaining thermodynamic parameters of binding, we have to consider the following multiple equilibrium between histone (H) and porphyrin (P): …”

“…These observations have been previously confirmed by spectroscopic techniques. 19 Estimated thermodynamic parameters represent the binding processes of TSPP and MnTSPP are considerable exothermic but for TAPP, it is endothermic for first ligand and unconsiderable exothermic for second ligand. With respect to positive charge of histone and negative charge of TSPP and MnTSPP, it can be concluded that columbic attraction has considerable role in the process of binding.…”

“…19 Since there are no reports on the microcalorimetry and thermodynamic study on the binding of porphyrins to histone, we were interested to investigate the interaction of three water soluble porphyrins (scheme 1 and 2), tetra (p-trimethyle) ammonium phenyl porphyrin iodide (TAPP) as a cationic porphyrin, tetra sodium meso-tetrakis (p-sulphonato phenyle) porphyrin (TSPP) as an anionic porphyrin and manganese tetrakis (psulphonato phenyl) porphinato acetate (MnTSPP) as a metal porphyrin, with histone H 2 B by isothermal titration microcalorimetry. The thermodynamic parameters of binding have been estimated from heat values of a stepwise calorimetric titration experiment by a modified simple graphical method which has been previously used for data analysis of simple systems.…”