131-83-9Relevant articles and documents
Sinsheimer et al.
, p. 13,17 (1955)
Cohn
, p. 2811 (1950)
Cleavage and isomerization of UpU promoted by dinuclear metal ion complexes
Linjalahti, Heidi,Feng, Guoqiang,Mareque-Rivas, Juan C.,Mikkola, Satu,Williams, Nicholas H.
, p. 4232 - 4233 (2008)
The catalysis of phosphoryl transfer by metal ions has been intensively studied in both biological and artificial systems, but the status of the transient pentacoordinate phosphoryl species (as transition state or intermediate) is the subject of considerable debate. We report that dinuclear metal ion complexes that incorporate second sphere hydrogen bond donors not only promote the cleavage of RNA fragments just as efficiently as the activated analogue HPNPP but also provide the first examples of metal ion catalyzed phosphate diester isomerization close to neutral pH. This observation implies that the reaction catalyzed by these complexes involves the formation of a phosphorane intermediate that is sufficiently long-lived to pseudorotate. Copyright
Substrate specificity of an active dinuclear Zn(II) catalyst for cleavage of RNA analogues and a dinucleoside
O'Donoghue, Annmarie,Pyun, Sang Yong,Yang, Meng-Yin,Morrow, Janet R.,Richard, John P.
, p. 1615 - 1621 (2006)
The cleavage of the diribonucleoside UpU (uridylyl-3′-5′- uridine) to form uridine and uridine (2′,3′)-cyclic phosphate catalyzed by the dinuclear Zn(II) complex of 1,3-bis(1,4,7-triazacyclonon-1-yl)- 2-hydroxypropane (Zn2(1)(H2O)) has been studied at pH 7-10 and 25 °C. The kinetic data are consistent with the accumulation of a complex between catalyst and substrate and were analyzed to give values of kc (S-1), Kd (M), and kc/K d (M-1 s-1) for the Zn2(1)(H 2O)-catalyzed reaction. The pH rate profile of values for log k C/Kd for Zn2(1)(H2O)-catalyzed cleavage of UpU shows the same downward break centered at pH 7.8 as was observed in studies of catalysis of cleavage of 2-hydroxypropyl-4-nitrophenyl phosphate (HpPNP) and uridine-3′-4-nitrophenyl phosphate (UpPNP). At low pH, where the rate acceleration for the catalyzed reaction is largest, the stabilizing interaction between Zn2(1)(H2O) and the bound transition states is 9.3, 7.2, and 9.6 kcal/mol for the catalyzed reactions of UpU, UpPNP, and HpPNP, respectively. The larger transition-state stabilization for Zn 2(1)(H2O)-catalyzed cleavage of UpU (9.3 kcal/mol) compared with UpPNP (7.2 kcal/mol) provides evidence that the transition state for the former reaction is stabilized by interactions between the catalyst and the C-5′-oxyanion of the basic alkoxy leaving group.
Buffer catalyzed cleavage of uridylyl-3′,5′-uridine in aqueous DMSO: Comparison to its activated analog, 2-hydroxypropyl 4-nitrophenyl phosphate
Lain,L?nnberg,L?nnberg
, p. 3484 - 3492 (2015)
Buffer catalysis of the cleavage and isomerization of uridylyl-3′,5′-uridine (UpU) has been studied over a wide pH range in 80% aq. DMSO. The diminished hydroxide ion concentration in this solvent system made catalysis by amine buffers (morpholine, 4-hydroxypiperidine and piperidine) visible even at relatively low buffer concentrations (10-200 mmol L-1). The observed catalysis was, however, much weaker than what has been previously reported for the activated RNA model 2-hydroxypropyl 4-nitrophenyl phosphate (HPNP) in the same solvent system. In the case of morpholine, contribution of both the acidic and the basic buffer constituent was significant, whereas with 4-hydroxypiperidine and piperidine participation of the acidic constituent could not be established unambiguously. The results underline the importance of using realistic model compounds, along with activated ones, in the study of the general acid/base catalysis of RNA cleavage.
Saffhill
, p. 2881 (1970)
Dinuclear Zn2+ complexes in the hydrolysis of the phosphodiester linkage in a diribonucleoside monophosphate diester.
Yashiro, Morio,Kaneiwa, Hideki,Onaka, Kenichi,Komiyama, Makoto
, p. 605 - 610 (2007/10/03)
Dizinc complexes that were formed from 2:1 mixtures of Zn(NO3)2 and dinucleating ligands TPHP (1), TPmX (2) or TPpX (3) in aqueous solutions efficiently hydrolyzed diribonucleoside monophosphate diesters (NpN) under mild conditions. The dinucleating ligand affected the structure of the aquo-hydroxo-dizinc core, resulting in different characteristics in the catalytic activities towards NpN cleavage. The pH-rate profile of ApA cleavage in the presence of (Zn2+)(2)-1 was sigmoidal, whereas those of (Zn2+)(2)-2 and (Zn2+)(2)-3 were bell-shaped. The pH titration study indicated that (Zn2+)(2)-1 dissociates only one aquo proton (up to pH 12), whereas (Zn2+)(2)-2 dissociates three aquo protons (up to pH 10.7). The observed differences in the pH-rate profile are attributable to the various distributions of the monohydroxo-dizinc species, which are responsible for NpN cleavage. As compared to that using (Zn2+)(2)-1, the NpN cleavage using (Zn2+)(2)-2 showed a greater rate constant, with a higher product ratio of 3'-NMP/2'-NMP. The saturation behaviors of the rate, with regard to the concentration of NpN, were analyzed by Michaelis-Menten type kinetics. Although the binding of (Zn2+)(2)-2 to ApA was weaker than that of (Zn2+)(2)-1, (Zn2+)(2)-2 showed a greater kcat value than (Zn2+)(2)-1, resulting in higher ApA cleavage activity of the former.
