84-53-7Relevant articles and documents
Guanidine-based polymer brushes grafted onto silica nanoparticles as efficient artificial phosphodiesterases
Savelli, Claudia,Salvio, Riccardo
, p. 5856 - 5863 (2015/03/31)
Polymer brushes grafted to the surface of silica nanoparticles were fabricated by atom-transfer radical polymerization (ATRP) and investigated as catalysts in the cleavage of phosphodiesters. The surfaces of silica nanoparticles were functionalized with an ATRP initiator. Surface-initiated ATRP reactions, in varying proportions, of a methacrylate moiety functionalized with a phenylguanidine moiety and an inert hydrophilic methacrylate species afforded hybrid nanoparticles that were characterized with potentiometric titrations, thermogravimetric analysis, and SEM. The activity of the hybrid nanoparticles was tested in the transesterification of the RNA model compound 2-hydroxypropyl para-nitrophenylphosphate (HPNP) and diribonucleoside monophosphates. A high catalytic efficiency and a remarkable effective molarity, thus overcoming the effective molarities previously observed for comparable systems, indicate the existence of an effective cooperation of the guanidine/guanidinium units and a high level of preorganization in the nanostructure. The investigated system also exhibits a marked and unprecedented selectivity for the diribonucleoside sequence CpA. The results presented open up the way for a novel and straightforward strategy for the preparation of supramolecular catalysts.
An RNA modification with remarkable resistance to RNase A
Ghidini, Alice,Ander, Charlotte,Winqvist, Anna,Stroemberg, Roger
supporting information, p. 9036 - 9038 (2013/09/24)
A 3′-deoxy-3′-C-methylenephosphonate modified diribonucleotide is highly resistant to degradation by spleen phosphodiesterase and not cleaved at all by snake venom phosphodiesterase. The most remarkable finding is that, despite the fact that both the vicinal 2-hydroxy nucleophile and the 5′-oxyanion leaving group are intact, the 3′-methylenephosponate RNA modification is also highly resistant towards the action of RNase A.
Tethered dinuclear europium(III) macrocyclic catalysts for the cleavage of RNA
Nwe, Kido,Andolina, Christopher M.,Morrow, Janet R.
body text, p. 14861 - 14871 (2009/02/08)
Dinuclear europium(III) complexes of the macrocycles 1,3-bis[1-(4,7,10- tris(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane]-m-xylene (1), 1,4-bis[1-(4,7,10-tris(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane] -p-xylene (2), and mononuclear europium(III) complexes of macrocycles 1-methyl-,4,7,10-tris(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane (3), 1-[3′-(N,N-diethylaminomethyl)benzyl]-4,7,10-tris(carbamoylmethyl)-1,4,7, 10-tetraazacyclododecane (4), and 1,4,7-tris(carbamoylmethyl)-1,4,7,10- tetraazacyclododecane (5) were prepared. Studies using direct excitation ( 7F0 → 5D0) europium(III) luminescence spectroscopy show that each Eu(III) center in the mononuclear and dinuclear complexes has two water ligands at pH 7.0, I = 0.10 M (NaNO 3) and that there are no water ligand ionizations over the pH range of 7-9. All complexes promote cleavage of the RNA analogue 2-hydroxypropyl-4- nitrophenyl phosphate (HpPNP) at 25°C (I = 0.10 M (NaNO3), 20 mM buffer). Second-order rate constants for the cleavage of HpPNP by the catalysts increase linearly with pH in the pH range of 7-9. The second-order rate constant for HpPNP cleavage by the dinuclear Eu(III) complex (Eu2(1)) at pH 7 is 200 and 23-fold higher than that of Eu(5) and Eu(3), respectively, but only 7-fold higher than the mononuclear complex with an aryl pendent group, Eu(4). This shows that the macrocycle substituent modulates the efficiency of the Eu(III) catalysts. Eu2(1) promotes cleavage of a dinucleoside, uridylyl-3′,5′-uridine (UpU) with a second-order rate constant at pH 7.6 (0.021 M-1 s-1) that is 46-fold higher than that of the mononuclear Eu(5) complex. Methyl phosphate binding to the Eu(III) complexes is energetically most favorable for the best catalysts, and this supports an important role for the catalyst in stabilization of the developing negative charge on the phosphorane transition state. Despite the formation of a bridging phosphate ester between the two Eu(III) centers in Eu2(1) as shown by luminescence spectroscopy, the two metal ion centers are only weakly cooperative in cleavage of RNA and RNA analogues.
