Analysis of O2′-Methylnucleoside 5′-Phosphates in Snake Venom Hydrolysates of RNA: Identification of O2′-Methyl-5-Carboxymethyluridine as a Constituent of Yeast Transfer RNA

1975 ◽  
Vol 53 (7) ◽  
pp. 735-746 ◽  
Author(s):  
M. W. Gray

Snake venom phosphodiesterase liberates the O2′-methylnucleoside (Nm) constituents of RNA as the corresponding 5′-nucleotides (pNm), which, in contrast to normal 5′-nucleotides (pN), are resistant to dephosphorylation by venom 5′-nucleotidase. This property provides the basis of a convenient and highly reproducible quantitative assay for Nm residues in RNA. The assay method involves: (1) hydrolysis of RNA with whole or partially-purified snake venom; (2) isolation of the pNm derivatives, as a group, by anion-exchange chromatography on DEAE-cellulose; (3) resolution of the individual pNm compounds by two-dimensional paper chromatography; (4) identification and quantitative measurement of pNm derivatives by ultraviolet absorption spectrophotometry. Using this procedure, the molar proportions of the Nm constituents of wheat embryo, yeast, and Escherichia coli tRNA have been determined. The close correspondence between the values measured by venom hydrolysis and those obtained by analysis of alkali-stable dinucleotide (Nm-Np) sequences attests to the validity of the venom assay, and further indicates that alkali-stable sequences larger than dinucleotides are not present in significant amounts in the tRNA of the above three organisms.During the present investigation, several ultraviolet-absorbing components, not immediately identifiable as ribose-methylated nucleotides, were isolated along with the expected O2′-methylnucleoside 5′-phosphates. Preliminary characterization of one of these compounds suggests that it is a derivative of a novel nucleoside, O2′-methyl-5-carboxymethyluridine (cm5Um). Venom hydrolysis of yeast tRNA liberates the 5′-nucleotide of cm5Um in the form of a carboxyl-blocked derivative (pU-2). During alkaline hydrolysis of yeast tRNA, the blocking group in U-2 is labilized and cm5Um is released as part of an alkali-stable dinucleotide, cm5Um-Ap. The proportion of pU-2 in venom hydrolysates of yeast tRNA (0.02 mol%, the same as the content of cm5Um-Ap in alkaline hydrolysates) suggests that O2′-methyl-5-carboxymethyluridine may be confined to a single isoaccepting species of tRNA in yeast.In an allied study, reinvestigation of the alkali-stable dinucleotide sequences of baker's yeast tRNA has confirmed previous results concerning the sequence distribution of O2′-methylribose in yeast tRNA (Gray, M. W. &Lane, B. G. (1967) Biochim. Biophys. Acta 134, 243–257).

1968 ◽  
Vol 46 (1) ◽  
pp. 81-92 ◽  
Author(s):  
B. D. McLennan ◽  
B. G. Lane

Snake venom phosphodiesterase induces about fifteen exonucleolytic cleavages for each endonucleolytic cleavage during the first hour of hydrolysis of wheat embryo ribosomal RNA, under the conditions of hydrolysis used in this present investigation. The polynucleotide chains in the ribosomal RNA preparation have an average degree of polymerization in the neighborhood of 1300 nucleotide residues, and there is a mean of between 5 and 10 endonucleolytic breaks per chain during this first hour of phosphodiesterase-induced hydrolysis. The cleavages occur widely throughout most of the polynucleotide chains in the ribosomal RNA preparation, as judged by the sharp decrease in mean sedimentation rate which accompanies a limited degree (about 10%) of exonucleolysis of the RNA. Studies of phosphodiesterase-induced endonucleolysis of wheat embryo soluble RNA are reported, but because of the much lower initial degree of polymerization (about 80 nucleotide residues per polynucleotide chain), the results of endonucleolysis are less pronounced in terms of the proportional increment in chain termini and the proportional decrease of mean sedimentation rate. The endonucleolysis of RNA is discussed in terms of the minor nucleotide components in both ribosomal and soluble RNA, and particular reference is made to pseudouridylate which has been found in relatively high proportion among the chain termini after limited hydrolysis with venom phosphodiesterase.Purified venom phosphodiesterase preparations, devoid of ribonuclease or 5′-nucleotidase contamination, were found to convert nucleoside 2′(3′),5′-diphosphates to 5′-nucleotides under conditions which had virtually no effect on nucleoside 3′-phosphates or nucleoside 5′-phosphates. The possibility that this reaction may be catalyzed by the venom phosphodiesterase itself is discussed.


1976 ◽  
Vol 54 (5) ◽  
pp. 413-422 ◽  
Author(s):  
M. W. Gray

A procedure for the quantitative measurement of the O2′-methylnucleoside constituents of RNA has recently been developed in this laboratory (Gray, M. W. Can. J. Biochem. 53,735–746 (1975)). This assay method is based on the resistance of O2′-methylnucleoside 5′-phosphates (pNm) (generated by phosphodiesterase hydrolysis of RNA) to subsequent dephosphorylation by venom 5′-nucleotidase (EC 3.1.3.5). In the present investigation, two base-modified 5′-nucleotides, each displaying an unusual resistance to 5′-nucleotidase, have been identified. These compounds have been characterized by a variety of techniques as N2,N2-dimethylguanosine 5′-phosphate [Formula: see text] and 3-(3-amino-3-carboxypropyl)uridine 5′-phosphate (p4abu3U). Because of their resistance to 5′-nucleotidase, [Formula: see text] and p4abu3U are isolated along with the pNm in the mononucleotide fraction of venom hydrolysates of transfer RNA.Under hydrolysis conditions, the stability of p4abu3U is comparable to that of a pNm, allowing quantitative assay of the nucleotide. The proportion (mean ± SD) of p4abu3U in venom hydrolysates of wheat embryo and Escherichia coli tRNA has been determined to be 0.35 ± 0.03 (n = 5) and 0.14 ± 0.02 (n = 4) mol%, respectively. The absence of p4abu3U in venom hydrolysates of yeast tRNA implies the absence of the corresponding nucleoside in yeast tRNA, in agreement with existing data. The variable recovery of [Formula: see text] from venom hydrolysates of wheat embryo and yeast tRNA indicates that under hydrolysis conditions, this base-modified nucleotide is only partially resistant to 5′-nucleotidase. The complete absence of[Formula: see text] in venom hydrolysates of E. coli tRNA is consistent with the known absence of N2,N2-dimethylguanosine in this RNA. These observations demonstrate that resistance to 5′-nucleotidase is a necessary but not sufficient criterion for concluding that a 5′-nucleotide is O2′-methylated.When applied to wheat embryo ribosomal RNA, the analytical methods described in this report failed to reveal any compound having the distinctive charge properties of p4abu3U. It therefore appears that 1-methyl-3-(3-amino-3-carboxypropyl)pseudouridine, recently characterized as a constituent of the 18 S rRNA of Chinese hamster cells (Saponara, A. G. &Enger, M. D. Biochim. Biophys. Acta 349,61–77 (1974)), may not be present in wheat embryo ribosomal RNA.


1980 ◽  
Vol 187 (3) ◽  
pp. 647-653 ◽  
Author(s):  
K Arakawa ◽  
M Yuki ◽  
M Ikeda

Tryptensin, a vasopressor substance generated from human plasma protein fraction IV-4 by trypsin, has been isolated and the amino acid composition analysed. The procedures used for the isolation were: (a) adsorption of the formed tryptensin on Dowex 50W (X2; NH4+ form); (b) gel filtration through Sephadex G-25; (c) cation-exchange chromatography on CM-cellulose; (d) anion-exchange chromatography on DEAE-cellulose; (e) re-chromatography on CM-cellulose; (f) gel filtration on Bio-Gel P-2; (g) partition chromatography on high-pressure liquid chromatography. The homogeneity of the isolated tryptensin was confirmed by thin-layer chromatography and thin-layer electrophoresis. The amino acid analysis of the hydrolysate suggested the following proportional composition: Asp, 1; Val, 1; Ile, 1; Tyr, 1; Phe, 1; His, 1; Arg, 1; Pro, 1. This composition is identical with that of human angiotensin.


2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Sunil Kumar Singh ◽  
Meera Yadav ◽  
Sudha Yadava ◽  
Kapil Deo Singh Yadav

Mn peroxidase has been purified to homogeneity from the culture filtrate of a new fungal strainFomes durissimusMTCC-1173 using concentration by ultrafiltration and anion exchange chromatography on diethylaminoethyl (DEAE) cellulose. The molecular mass of the purified enzyme has been found to be 42.0 kDa using SDS-PAGE analysis. The values using MnSO4and H2O2as the variable substrates in 50 mM lactic acid-sodium lactate buffer pH 4.5 at were 59 μM and 32 μM, respectively. The catalytic rate constants using MnSO4and H2O2were 22.4 s−1and 14.0 s−1, respectively, giving the values of 0.38 μM−1s−1and 0.44 μM−1s−1, respectively. The pH and temperature optima of the Mn peroxidase were 4 and , respectively. The purified MnP depolymerises humic acid in presence of H2O2. The purified Mn peroxidase exhibits haloperoxidase activity at low pH.


2011 ◽  
Vol 31 (6) ◽  
pp. 465-475 ◽  
Author(s):  
Syed Rashel Kabir ◽  
Md. Abu Zubair ◽  
Md. Nurujjaman ◽  
Md. Azizul Haque ◽  
Imtiaj Hasan ◽  
...  

A lectin (termed NNTL) was purified from the extracts of Nymphaea nouchali tuber followed by anion-exchange chromatography on DEAE-cellulose, hydrophobic chromatography on HiTrap Phenyl HP and by repeated anion-exchange chromatography on HiTrap Q FF column. The molecular mass of the purified lectin was 27.0 ± 1.0 kDa, as estimated by SDS/PAGE both in the presence and in the absence of 2-mercaptoethanol. NNTL was an o-nitrophenyl β-D-galactopyranoside sugar-specific lectin that agglutinated rat, chicken and different groups of human blood cells and exhibited high agglutination activity over the pH range 5–9 and temperatures of 30–60°C. The N-terminal sequence of NNTL did not show sequence similarity with any other lectin and the amino acid analysis revealed that NNTL was rich in leucine, methionine and glycine residues. NNTL was a glycoprotein containing 8% neutral sugar and showed toxicity against brine shrimp nauplii with an LC50 value of 120 ± 29 μg/ml and exerted strong agglutination activity against four pathogenic bacteria (Bacillus subtilis, Sarcina lutea, Shigella shiga and Shigella sonnei). In addition, antiproliferative activity of this lectin against EAC (Ehrlich ascites carcinoma) cells showed 56% and 76% inhibition in vivo in mice at 1.5 and 3 mg·kg−1·day−1 respectively. NNTL was a divalent ion-dependent glycoprotein, which lost its activity markedly in the presence of denaturants. Furthermore, measurement of fluorescence spectra in the presence and absence of urea and CaCl2 indicated the requirement of Ca2+ for the stability of NNTL.


1987 ◽  
Vol 42 (4) ◽  
pp. 387-393 ◽  
Author(s):  
Hilda-K. Hund ◽  
Brigitte Keller ◽  
Franz Lingens

Abstract The enzymes of the terminal steps of phenylalanine and tyrosine biosynthesis, chorismate mutase, prephenate dehydratase, arogenate dehydratase, prephenate dehydrogenase and aroge­ nate dehydrogenase were studied in 13 sporeforming members of the order Actinomycetales. In these organisms tyrosine is synthesized exclusively via arogenate, phenylalanine, however, via phenylpyruvate. The regulation pattern of the corresponding enzymes was determined: No feed­ back inhibition of arogenate dehydrogenase by L-phenylalanine and ʟ-tyrosine was observed. Chorismate mutase was found to be inhibited in all organisms by ʟ-tyrosine and in most organisms by ʟ-tryptophan. ʟ-Phenylalanine was shown to inhibit prephenate dehydratase in the majority of bacteria tested and ʟ-tyrosine activated this enzyme in most cases. The elution profiles for the phenylalanine and tyrosine biosynthetic enzymes were studied in three members of the order Actinomycetales by anion exchange chromatography on DEAE-cellulose.


1980 ◽  
Vol 33 (3) ◽  
pp. 279 ◽  
Author(s):  
RN Murdoch ◽  
Louise E Buxton ◽  
DJ Kay

An improved procedure for the purification of alkaline phosphatase from about 10 g of day 7 pregnant mouse uterine tissue is described. Following homogenization, the procedure involved solubilization and extraction with 0�8% (v/v) Triton X-lOO and 20% (v/v) n-butanol, ammonium sulfate precipitation, concanavalin A-Sepharose 4B affinity chromatography, DEAE-cellulose anion-exchange chromatography and Sephacryl S200 gel filtration. On subjecting 2162-fold purified enzyme preparations to polyacrylamide-gel electrophoresis, a single band of protein coincident with the zone of enzyme activity and having an apparent molecular weight of 205 OOO� lOOOO was identified. Affinity chromatography yielded the largest increase in purity of any step in the procedure and established the glycoprotein nature of the uterine enzyme.


2015 ◽  
Vol 16 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Theerasak Somdee ◽  
Anchana Somdee

For the first time, different types of diethylaminoethyl (DEAE) anion-exchange resins, widely used in previous studies, were investigated to determine the most effective resin for the purification of microcystins (MCs). MCs were extracted from freeze-dried Microcystis aeruginosa cells that had been harvested from the Bueng Nong Khot reservoir, Khon Kaen, Thailand. The toxins were precipitated with ammonium sulfate and then fractionated using five different anion-exchange chromatography resins, followed by chromatography with a C18 cartridge. The toxins were further identified via liquid chromatography–electrospray ionization–mass spectrometry (LC-ESI-MS) analysis, and the yields and purity were determined by high-performance liquid chromatography (HPLC) with ultraviolet detection. DEAE Sephadex A-25 exhibited the best overall performance for MC purification regarding both yield and purity, followed by DEAE cellulose, DEAE Sephacel, DEAE Sepharose Fast Flow and Toyopearl DEAE. Four MC variants, MC-RR, MC-FR, [Dha7]MC-LR and MC-WR, were obtained, and [Dha7]MC-LR was the major variant, with a total yield of 53.08 mg and a purity of 95% using the Sephadex resin. This study indicates that protein precipitation and single-column chromatography using DEAE Sephadex A-25 constitute an effective method for the purification of a wide range of MC variants.


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