Polynucleotide: adenosine glycosidase activity of saporin-L1: effect on DNA, RNA and poly(A)

The ribosome-inactivating proteins (RIPs) are a family of plant enzymes for which a unique activity has been determined: rRNA N-glycosidase, which removes adenine at a specific universally conserved position (A4324 in the case of rat ribosomes). Here we report that saporin-L1, a RIP from the leaves of Saponaria officinalis, recognizes other substrates, including RNAs from different sources, DNA and poly(A). Saporin-L1 depurinated DNA extensively and released adenine from all adenine-containing polynucleotides tested. Adenine was the only base released from DNA or artificial polynucleotides. The characteristics of the reactions catalysed by saporin-L1 have been determined: optimal pH and temperature, ionic requirements, and the kinetic parameters Km and kcat. The reaction proceeded without cofactors, at low ionic strength, in the absence of Mg2+ and K+. Saporin-L1 had no activity towards various adenine-containing non-polynucleotide compounds (cytokinins, cofactors, nucleotides). This plant protein may now be classified as a polynucleotide:adenosine glycosidase.

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Consistency issues of aqueous solubility data and solution thermodynamics of electrolytes

Pure and Applied Chemistry ◽

10.1351/pac200577030619 ◽

2005 ◽

Vol 77 (3) ◽

pp. 619-629 ◽

Cited By ~ 6

Author(s):

Alex De Visscher ◽

Jan Vanderdeelen

Keyword(s):

Calcium Carbonate ◽

Ionic Strength ◽

Thermodynamic Data ◽

Pitzer Model ◽

Aqueous Solubility ◽

Ion Pair ◽

Empirical Equations ◽

Low Ionic Strength ◽

Semi Empirical ◽

Different Sources

For the calculation of aqueous solubility of electrolytes, thermodynamic data from different sources are required. This can lead to errors if the data are inconsistent. This study reveals that some often-used semi-empirical equations for CO2 solubility and other equilibria are inconsistent with CODATA (Committee on Data for Science and Technology) key thermodynamic data. The equations were recalculated to make them consistent with CODATA. Combining standard thermodynamic data of NaCl with the Pitzer model leads to significant deviations from the accepted experimental value at 25 °C. Owing to the inadequacy of the Pitzer model at molalities exceeding 6 mol kg–1, this model leads to poor predictions of the HCl vapor pressure in equilibrium with highly concentrated aqueous HCl solutions. A long-standing inconsistency problem is related to the solubility of calcium carbonate. The main problem is disagreement on the existence of the CaHCO3+ ion pair. It is shown that the inconsistency largely disappears if it is assumed that the CaHCO3+ exists at low ionic strength, but becomes less stable at higher ionic strength.

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Conformational Transitions in Escherichia coli Ribosomal RNAs as Visualized by Dedicated STEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100102961 ◽

1988 ◽

Vol 46 ◽

pp. 176-177

Author(s):

J.S. Wall ◽

V. Maridiyan ◽

S. Tumminia ◽

J. Hairifeld ◽

M. Boublik

Keyword(s):

Ionic Strength ◽

Three Dimensional ◽

Conformational Transitions ◽

Dark Field ◽

Dimensional Structure ◽

Ribosomal Rnas ◽

Field Mode ◽

Freeze Dried ◽

High Resolution Images ◽

Low Ionic Strength

The high contrast in the dark-field mode of dedicated STEM, specimen deposition by the wet film technique and low radiation dose (1 e/Å2) at -160°C make it possible to obtain high resolution images of unstained freeze-dried macromolecules with minimal structural distortion. Since the image intensity is directly related to the local projected mass of the specimen it became feasible to determine the molecular mass and mass distribution within individual macromolecules and from these data to calculate the linear density (M/L) and the radii of gyration.2 This parameter (RQ), reflecting the three-dimensional structure of the macromolecular particles in solution, has been applied to monitor the conformational transitions in E. coli 16S and 23S ribosomal RNAs in solutions of various ionic strength.In spite of the differences in mass (550 kD and 1050 kD, respectively), both 16S and 23S RNA appear equally sensitive to changes in buffer conditions. In deionized water or conditions of extremely low ionic strength both appear as filamentous structures (Fig. la and 2a, respectively) possessing a major backbone with protruding branches which are more frequent and more complex in 23S RNA (Fig. 2a).

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An Evaluation of a Plasma Fractionation System

Thrombosis and Haemostasis ◽

10.1055/s-0038-1654486 ◽

1960 ◽

Vol 4 (01) ◽

pp. 031-044

Author(s):

George Y. Shinowara ◽

E. Mary Ruth

Keyword(s):

Biological Activity ◽

Ionic Strength ◽

Plasma Proteins ◽

High Concentration ◽

Significant Evidence ◽

Native Proteins ◽

Mobility Data ◽

Fractionation Procedure ◽

The Individual ◽

Low Ionic Strength

SummaryFour primary fractions comprising at least 97 per cent of the plasma proteins have been critically appraised for evidence of denaturation arising from a low temperature—low ionic strength fractionation system. The results in addition to those referable to the recovery of mass and biological activity include the following: The high solubilities of these fractions at pH 7.3 and low ionic strengths; the compatibility of the electrophoretic and ultracentrifugal data of the individual fractions with those of the original plasma; and the recovery of hemoglobin, not hematin, in fraction III obtained from specimens contaminated with this pigment. However, the most significant evidence for minimum alterations of native proteins was that the S20, w and the electrophoretic mobility data on the physically recombined fractions were identical to those found on whole plasma.The fractionation procedure examined here quantitatively isolates fibrinogen, prothrombin and antithrombin in primary fractions. Results have been obtained demonstrating its significance in other biological systems. These include the following: The finding of 5 S20, w classes in the 4 primary fractions; the occurrence of more than 90 per cent of the plasma gamma globulins in fraction III; the 98 per cent pure albumin in fraction IV; and, finally, the high concentration of beta lipoproteins in fraction II.

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Report on the U.S. Geological Survey's evaluation program for standard reference samples distributed in October 1993 : T-127 (trace constituents), M-128 (major constituents), N-40 (nutrients), N-41 (nutrients), P-21 (low ionic strength), Hg-17 (mercury), AMW-3 (acid mine water), and WW-1 (whole water)

Open-File Report ◽

10.3133/ofr9442 ◽

1994 ◽

Author(s):

H.K. Long ◽

J.W. Farrar

Keyword(s):

Ionic Strength ◽

Mine Water ◽

Acid Mine Water ◽

Evaluation Program ◽

Acid Mine ◽

Trace Constituents ◽

Low Ionic Strength ◽

Reference Samples ◽

The U.S ◽

Whole Water

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Results of the U.S. Geological Survey's Analytical Evaluation Program for standard reference samples: T-155 (trace constituents), M-148 (major constituents), N-59 (nutrient constituents), N-60 (nutrient constituents), P-31 (low ionic strength constituents), GWT-4 (ground-water trace constituents) and Hg-27 (Mercury) distributed in September 1998

Open-File Report ◽

10.3133/ofr9972 ◽

1999 ◽

Cited By ~ 1

Author(s):

Jerry W. Farrar

Keyword(s):

Ionic Strength ◽

Ground Water ◽

Analytical Evaluation ◽

Evaluation Program ◽

Trace Constituents ◽

Low Ionic Strength ◽

Reference Samples ◽

The U.S

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A novel procedure for the rapid purification of plastocyanin from pea (Pisum sativum) leaves

Biochemical Journal ◽

10.1042/bj1930375 ◽

1981 ◽

Vol 193 (1) ◽

pp. 375-378 ◽

Cited By ~ 4

Author(s):

A R Ashton ◽

L E Anderson

Keyword(s):

Ionic Strength ◽

Pisum Sativum ◽

Deae Cellulose ◽

High Concentrations ◽

Rapid Purification ◽

Low Ionic Strength

Plastocyanin is soluble at high concentrations (greater than 3 M) of (NH4)2SO4 but under these conditions will adsorb tightly to unsubstituted Sepharose beads. This observation was utilized to purify plastocyanin from pea (Pisum sativum) in two chromatographic steps. Sepharose-bound plastocyanin was eluted with low-ionic-strength buffer and subsequently purified to homogeneity by DEAE-cellulose chromatography.

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