Probing the effect of minor groove interactions on the catalytic efficiency of DNAzymes 8–17 and 10–23

DNAzymes (Dz) 8–17 and 10–23 are two widely studied and well-characterized RNA-cleaving DNA catalysts. In an effort to further improve the understanding of the fragile interactions and dynamics of the enzymatic mechanism, this study examines the catalytic efficiency of minimally modified DNAzymes. Five single mutants of Dz8–17 and Dz10–23 were prepared by replacing the adenine residues in the corresponding catalytic cores with 3-deazaadenine units. Kinetic assays were used to assess the effect on the catalytic activity and thereby identify the importance of hydrogen bonding that arises from the N3 atoms. The results suggest that modifications at A15 and A15.0 of Dz8–17 have a significant influence and show a reduction in catalytic activity. Modification at each location in Dz10–23 results in a decrease of the observed rate constants, with A12 appearing to be the most affected with a reduction of ∼80% of kobs and ∼25% of the maximal cleavage rate compared to the wild-type DNAzyme. On the other hand, modification of A12 in Dz8–17 showed an ∼130% increase in kobs, thus unraveling a new potential site for the introduction of chemical modifications. A pH-profile analysis showed that the chemical cleavage step is rate-determining, regardless of the presence and/or location of the mutation. These findings point towards the importance of the N3-nitrogens of certain adenine nucleotides located within the catalytic cores of the DNAzymes for efficient catalytic activity and further suggest that they might directly partake in maintaining the appropriate tertiary structure. Therefore, it appears that minor groove interactions constitute an important feature of DNAzymes as well as ribozymes.

Die hebräische Presse im Jahre 1912 : (Fortsetzung von Seite 167/168)

Josef Lin

Rabbi Jitzchak Alfasi [Illustration] : 1023 - 1103

Scan von Monochrom-Mikroform

Ms. Barth. 168 - Theologische Sammelhandschrift

Vorbesitzer: Brune-Kütze-Legat; Bartholomaeusstift Frankfurt am Main

Ms. Praed. 168 - Funiculus triplex

Vorbesitzer: Dominikanerkloster Frankfurt am Main

Na 50 Nachlass Arthur Schopenhauer - 'Schopenhauer-Archiv', 1023 - Frage zu den Besitzverhältnissen in den Ohraschen Gütern bei Danzig

u.a. Geburtshaus von Johanna Schopenhauer;

Na 50 Nachlass Arthur Schopenhauer - 'Schopenhauer-Archiv', 168 - Nachdrückliche Bitte von Herrn Dr. Kastner um Verschwiegenheit wegen des vorausgegangenen Bittschreibens

Abschrift liegt vor

Ms.Ff.F.Stoltze 3. 168 - Brief von Theobald Kerner an Friedrich Stoltze

Beschwerde wegen der Anrede "Hofrath", Übersendung eines Textes für einen Autographensammler, Übersendung eines Rings für Molly Stoltze zur Verlobung, Else Körner

Na 1 Nachlass Max Horkheimer, 446 - Korrespondenzen mit der UNESCO (p. V 168, 145-206)

Drucksachen und Schriftwechsel der UNESCO (Paris, Hamburg, Gauting), 1957-1965; 69 Briefe zwischen Dr. Gilda Mara, UNESCO und Max Horkheimer, 1959-1965; 12 Briefe zwischen Dr. Helga Timm, UNESCO und Max Horkheimer, 1957-1958;

Na 1 Nachlass Max Horkheimer, 520 - Korrespondenzen mit Walter Benjamin (Kopien) (p. VI 5A, 168 - 325)

4 Briefe zwischen Walter Benjamin und Cecilia Razovsky; 6 Briefe zwischen Cecilia Razovsky und Max Horkheimer; 1 Brief von Cecilia Razovsky an den American Consul, 17.11.1939; 1 Brief von Antonio Sols an Max Horkheimer, 30.10.1940; 1 Brief von Max Horkheimer an Antonio Sols, 11.10.1940; 1 Brief (Abschrift, Auszug) an A. R. L. Gurland von Frau Gurland, 11.10.1940; 3 Briefe zwischen dem Emergency Rescue Committee (New York) und Max Horkheimer, August 1940; 1 Brief von Max Horkheimer an Pastor del Rio, 17.07.1940; 1 Brief von Max Horkheimer an J. Wavrinek, 17.07.1940; 1 Brief von Theodor W. Adorno an Gershom Scholem, 16.07.1940; 1 Brief von Max Horkheimer an Hans Schaudinger, 13.07.1940; 1 Brief von Max Horkheimer an George S. Messersmith, 08.07.1940; 1 Brief von Max Horkheimer an Adolph Kates, 05.07.1940; 1 Brief von Max Horkheimer an Adolph Kates, 29.06.1940; 2 Briefe zwischen dem Refugee Section of the American Friends Service Committee (Philadelphia) und Max Horkheimer, Mai 1940; 2 Briefe von Egon Wissing an Max Horkheimer, 1940; 1 Brief von Max Horkheimer an die Economy Blue Print Co. (New York), 25.05.1940; 1 Brief von Werner Kraft an Max Horkheimer, 30.04.1940;

Über den altjüdischen Kalender, zunächst in seiner Beziehung zur neutestamentlichen Geschichte : eine kronologisch-kritische Untersuchung (zugleich ein Beitrag zur Evangelien-Harmonistik), nebst einem Anhang von Tafeln zur bequemen Berechnung altjüdischer Daten für den Zeitraum der Jahre 168 vor bis 72 nach Kr.

von Johannes von Gumpach

Na 1 Nachlass Max Horkheimer, 693 - "German Economy, Politics and Culture, 1900-1933" (p. IX 168 1.a)-d))

"German Economy, Politics and Culture, 1900-1933. A Research Project of the International Institute of Social Research" (1940):; 1. Umriß des Forschungsprojekts, a) Fassung vom 29.7.1940, Typoskript, 55 Blatt, b)-d) Fassung vom 6.6.1940: b) Typoskript, 55 Blatt, c) Typoskript mit handschriftlichen Korrekturen, 60 Blatt, d) Typoskript, 60 Blatt;

Ms. lat. oct. 168 - Quaestiones et disputationes theologicae

Vorbesitzer: Bernhard Waldschmidt;

Chlorine stable isotopic composition of basement fluids from ODP Leg 168 sites

This paper presents chlorine stable isotope compositions (delta37Cl) of sediment pore waters collected by squeezing sediment cores from the sediment-basement interface along an East-West transect through the eastern flank of the Juan de Fuca Ridge (ODP Leg 168). These "near basement fluids" (NBF) are generally thought to be representative of low-temperature fluids circulating in the off-axis basaltic crust. The delta37Cl value of the fluid directly sampled from a flow at the base of Site 1026 (WSTP1026) is also reported. NBF display delta37Cl values between -2.09? and -0.12? relative to the Standard Mean Ocean Chloride (SMOC defined as 0?) and small variations in chlorinity (~4%). These data contrast with the homogeneity of delta37Cl values associated with highly variable chlorinities observed in high-temperature on-axis fluids [Bonifacie et al., 2005, doi:10.1016/j.chemgeo.2005.06.008]. The NBF delta37Cl values show a general decreasing trend with distance from the ridge-axis except for two fluids. When plotted against delta18O values, the delta37Cl of the NBF show two different trends. This paper discusses the possible contributions on NBF delta37Cl values of fluid-mixing, water-rock interactions and transport processes (diffusion, ion membrane filtration) that can occur in the igneous basement. However, as none of these processes can fully explain the observed delta37Cl variations, the potential effect of the sediment cover is also investigated. At site 1026, the interstitial pore fluid displays a delta37Cl signature significantly lower than that of the fluid discharge sample (-1.90? and -0.28?, respectively). This difference, demonstrated here cannot be an artifact of the sampling method, rather indicates the influence of the sediment cover on NBF delta37Cl values. The potential contributions of physical processes associated with transport/compaction (e.g., diffusion, ion membrane filtration, adsorption, ion exchange) on NBF delta37Cl values are qualitatively discussed here but require additional studies for further insights. However, this study indicates that "near basement fluids" (NBF) are not, at least for Cl isotopic compositions, necessarily as representative of fluids circulating in the basaltic crust as initially thought. These results add new constraints on Cl geodynamics and show that Cl-isotopes fractionate during low-temperature circulation of fluids in off-axis and off-margin flow contexts, but not to the extent observed for active margins. Fluids circulating at low-temperature in the magmatic and/or the sedimentary part of the oceanic crust might have played a major role on the delta37Cl evolution of seawater over geologic time.