283 research outputs found
Higher-Order G-Quadruplex Structures and Porphyrin Ligands: An Ambiguous Relationship
No full textThe obtainment of tailored DNA nanostructures provided with structural and functional features useful for nanotechnological and medical applications represents one of the hottest topics in recent literature. In particular, the unusual DNA secondary structures known as G-quadruplexes, which form when guanine-rich DNA and RNA strands are annealed in the presence of physiological cations such as Na+ and K+, proved effective for the obtainment of DNA assemblies displaying in vitro anticancer1, antiviral2 or anticoagulant3 activity, mostly due to their ability to recognise and bind with high specificity and affinity their target proteins. It has been demonstrated that both the kinetics of formation and the stability of G-quadruplexes are affected not only by the nature and concentration of coordinating cations, but also by the presence of G-quadruplex ligands, including those having porphyrin-based core.4 In this communication, I will report the results of our recent studies on the effect of the addition of porphyrin-based derivatives on the stability and overall topology of G-quadruplex superstructure
Interaction of Tricationic Corroles with Single/Double Helix of Homopolymeric Nucleic Acids and DNA
No full textIn this manuscript a multitechnique approach is proposed to characterize the interaction between new tri-N-methylpyridyl corrole (TMPC) and its germanium(IV) derivative (GeTMPC), with single- and double-stranded nucleic acid homopolymers and calf thymus DNA The specificity of each spectroscopic technique has been exploited to analyze the different aspects of corrole binding. Noteworthy, this approach allows us to distinguish between H aggregation of TMPC in the presence of polyriboadenilic acid (poly(rA)) and J aggregates in the presence of polyribocytidinic acid (poly(rC)) as well as to identify the formation of GeTMPC dimers in the presence of single-stranded poly(rA) and pseudointercalation with single-stranded poly(rC)
Supramolecular structure of extrinsically chiral porphyrin hetero-assemblies and achiral analogues
No full textSupramolecular structures of porphyrin hetero-assemblies and the achiral analogous are determined through energy dispersive X-ray diffraction. In presence of phenylalanine, CuT4 cationic and H2TTPS anionic porphyrins yield a suprachiral alpha-helix persisting even after removing the chiral template. The analogous synthesis performed without the template-imprinting agent provides an amorphous arrangement, hence an achiral structure
Absorption flattening as one cause of distortion of circular dichroism spectra of Delta-RuPhen(3) . H(2)TPPS complex
No full textTo extend the model that explains why and how much absorption flattening
(AF) influences circular dichroism (CD) signals, we have investigated the interesting
case of exciton CD in the Soret region of a noncovalent complex formed by (DRuPhen3)
21 and the tetraanionic porphyrin H2TPPS. Different concentrations have been
studied by using an AF emulator and spectra simulation. The CD spectra of this compound
occasionally show distortions in the solution sampling mode with the increase of
concentration; the inhomogeneous distribution in the cell volume is due to aggregation
and is the source of the AF effect. On the basis of these results, we conclude that AF is
an important cause of distortions in CD spectra for D-RuPhen3 H2TPPS complexes and
might affect the CD bands of other aggregated systems as wel
Beneficial effect of lixisenatide after 76 weeks of treatment in patients with type 2 diabetes mellitus: A meta-analysis from the GetGoal programme
No full textTo evaluate the long-term efficacy and safety of lixisenatide, a short-acting, prandial glucagon-like peptide-1 receptor agonists (GLP-1 RA) as add-on therapy in type 2 diabetes mellitus
Combined Approach To Remove and Fast Detect Heavy Metals in Water Based on PES–TiO2 Electrospun Mats and Porphyrin Chemosensors
No full textHybrid poly(ether sulfones) (PES)-TiO2 electrospun mats are used as selective filters to remove lead and zinc ions from water. Presence of TiO2 is functional to trigger fiber's surface charge that allows for better performances in terms of ionic adsorption with respect to bare PES mats. Temperature increase promotes a speed up of ion removal. Ability of electrospun mats to retain adsorbed ions is proven by washing procedures, which confirm the lack of released Pb2+ in solution, even after sonication. To detect presence of metal ions in aqueous solutions, water-soluble porphyrins are used as chemosensors, which are able to provide fast, in-field, and real-time analysis. In particular, cationic H2T4 metalation, occurring both in solution or at transparent glass surface, allows for a straightforward spectrophotometric (UV-vis) detection of metal ions in solution
Chimica generale e inorganica
No full textManuale di Chimica Generale ad uso degli studenti dei corsi di laurea di tutte le facoltà che prevedono l'insegnamento dei fondamenti di chimica.An online platform (accessed by personal identification code) is associated with the book for self-assessment, tutoring, and deepening of the content
Design principles of chiral carbon nanodots help convey chirality from molecular to nanoscale level
No full textThe chirality of (nano)structures is paramount in many phenomena, including biological processes, self-assembly, enantioselective reactions, and light or electron spin polarization. In the quest for new chiral materials, metallo-organic hybrids have been attractive candidates for exploiting the aforementioned scientific fields. Here, we show that chiral carbon nanoparticles, called carbon nanodots, can be readily prepared using hydrothermal microwave-assisted synthesis and easily purified. These particles, with a mean particle size around 3 nm, are highly soluble in water and display mirror-image profile both in the UV–Vis and in the infrared regions, as detected by electronic and vibrational circular dichroism, respectively. Finally, the nanoparticles are used as templates for the formation of chiral supramolecular porphyrin assemblies, showing that it is possible to use and transfer the chiral information. This simple (and effective) methodology opens up exciting opportunities for developing a variety of chiral composite materials and applications.This work was supported by the University of Trieste, INSTM, AXA Research Fund, the Spanish Ministry of Economy and Competitiveness MINECO (project CTQ2016-76721-R), Diputación Foral de Gipuzkoa program Red (101/16) and ELKARTEK bmG2017 (Ref: Elkartek KK-2017/00008, BOPV resolution: 8 Feb 2018). R.P. and A.D. thank MIUR for financial support "Piano della Ricerca di Ateneo 2016–2018 linea di intervento 2". We would like to thank Dr. Jatish Kumar (CIC biomaGUNE), Prof. Lorenzo di Bari (Università di Pisa) and Prof. Marcella Bonchio (Università di Padova) for helpful discussions
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