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1.
Jacques Raymond Brahim Mimouni Jean-Louis Azanza 《Plant Systematics and Evolution》1994,193(1-4):69-79
The seed storage globulins from sixHelianthus and four hybrids were studied using mono and bidimensional gel SDS electrophoresis (+ 2 mercaptoethanol). The polypeptide composition of each subunit was determined. Different pairs are specifically expressed according to the species studied. Three typical patterns were discriminated. All the studied species exhibit five subunits: two of them are expressed in all the species (11 and 22). The subunit corresponding to the 11 pair is present inH. petiolaris and in the three populations ofH. annuus studied. The 2b2 pair is common toH. annuus andH. argophyllus. H. petiolaris presents two specific 2a2 and 44 pairs andH. annuus a specific 33 pair. InH. argophyllus 11 33 or 44 are never observed but are replaced by 13 and 31 pairs. Some globulins, poorly represented, are of forms but present chains of higher molecular weights (in the range 54–56 kDa). Expressing variations in the banding patterns between these species by the use of a similarity index reveals complete identity between the three populations ofH. annuus. Identity between the twoH. petiolaris studied is also observed.H. annuus andH. argophyllus appear to be closer to each other thanH. petiolaris concerning the seed storage globulins. 相似文献
2.
V. V. Litvak I. Ya. Mainagashev O. G. Bukhanets 《Russian Journal of Bioorganic Chemistry》2004,30(4):337-343
The interaction of 3,5-bis-O-(,,,-tetrafluoropyrid--yl)thymidine with various nucleophilic reagents was studied to evaluate the possibility of molecular design of new types of nucleic acid analogues using S
NAr reactions. The reactions with morpholine and sodium azide led to the introduction of one and two nucleophilic residues into each of the polyfluorinated pyridine rings. The nucleophilic polycondensation with bifunctional reagents ethylenediamine and hexamethylenediamine depended on the nature of nucleophile and reaction conditions and resulted in the formation of supramolecules containing about five or more than 20 pyrimidine bases. 相似文献
3.
Crude extracts or supernatants of broken cells of Clostridium formicoaceticum reduce unbranched, branched, saturated and unsaturated carboxylates at the expense of carbon monoxide to the corresponding alcohols. The presence of viologens with redox potentials varying from E
0=-295 to-650 mV decreased the rate of propionate reduction. The more the propionate reduction was diminished the more formate was formed from carbon monoxide. The lowest propionate reduction and highest formate formation was observed with methylviologen. The carbon-carbon double bond of E-2-methyl-butenoate was only hydrogenated when a viologen was present. Formate as electron donor led only in the presence of viologens to the formation of propanol from propionate. The reduction of propionate at the expense of a reduced viologen can be followed in cuvettes. With respect to propionate Michaelis Menten behavior was observed. Experiments are described which lead to the assumption that the carboxylates are reduced in a non-activated form. That would be new type of biological reduction.Non-standard abbreviations glc
Gas liquid chromatography
- HPLC
high performance liquid chromatography
- RP
reverse phase; Mediators (the figures in parenthesis of the mediators are redox potentials E
0 in mV)
- CAV2+
carbamoylmethylviologen, 1,1-carbamoyl-4,4-dipyridinium dication (E
0=-296 mV)
- BV2+
benzylviologen, 1,1-dibenzyl-4,4-dipyridinium dication (E
0=-360 mV)
- MV
methylviologen, 1,1-dimethyl-4,4-dipyridinium-dication (E
0=-444 mV)
- DMDQ2+
dimethyldiquat, 4,4-dimethyl-2,2-dipyridino-1,1-ethylendication (E
0=-514 mV)
- TMV2+
tetramethylviologen, 1,1,4,4-tetramethyl-4,4-dipyridinium dication (E
0=-550 mV)
- PDQ2+
propyldiquat, 2,2-dipyridino-1,1-propenyl dication (E
0=-550 mV)
- DMPDQ2+
dimethylpropyldiquat, 4,4-dimethyl-2,2-dipyridino-1,1-propenyl dication (E
0=-656 mV)
- PN
productivity number=mmol product (obtained by the uptake of one pair of electrons) x (biocatalyst (dry weight) kg)-1×h-1 相似文献
4.
The carotenoid pigments of a Rhizobium strain isolated from Lotononis bainesii were found to be diglucosyl-4,4-diapocarotene-4,4-dioate and glucosyl-4,4-diapocarotene-4-oate-4-oic acid.5th publication in the series Carotenoids of Rhizobia [4th publication: Helv. chim. Acta 62: 2551–2557 (1979)] 相似文献
5.
Ahlert Schmidt 《Archives of microbiology》1977,112(3):263-270
Crude extracts of Rhodospirillum rubrum catalyzed the formation of acid-volatile radioactivity from (35S) sulfate, (35S) adenosine-5-phosphosulfate, and (35S) 3-phosphoadenosine-5-phosphosulfate. An enzyme fraction similar to APS-sulfotransferases from plant sources was purified 228-fold from Rhodospirillum rubrum. It is suggested here that this enzyme is specific for adenosine-5-phosphosulfate, because the purified enzyme fraction metabolized adenosine-5-phosphosulfate, however, only at a rate of 1/10 of that with adenosine-5-phosphosulfate. Further, the reaction with 3-phosphoadenosine-5-phosphosulfate was inhibited with 3-phosphoadenosine-5-phosphate whereas this nucleotide had no effect on the reaction with adenosine-5-phosphosulfate. For this activity with adenosine-5-phosphosulfate the name APS-sulfotransferase is suggested. This APS-sulfotransferase needs thiols for activity; good rates were obtained with either dithioerythritol or reduced glutathione; other thiols like cysteine, 2-3-dimercaptopropanol or mercaptoethanol are less effective. The electron donor methylviologen did not catalyze this reaction. The pH-optimum was about 9.0; the apparent K
m for adenosine-5-phosphosulfate was determined to be 0.05 mM with this so far purified enzyme fraction. Enzyme activity was increased with K2SO4 and Na2SO4 and was inhibited by 5-AMP. These properties are similar to assimilatory APS-sulfotransferases from spinach and Chlorella.Abbreviations APS
adenosine-5-phosphosulfate
- PAPS
3-phosphoadenosine-5-phosphosulfate
- 5-AMP
adenosine-5-monophosphate
- 3-AMP
adenosine-3-monophosphate
- 3-5-ADP
3-phosphoadenosine-5-phosphate (PAP)
- DTE
dithiorythritol
- GSH
reduced glutathione
- BAL
2-3-dimercaptopropanol 相似文献
6.
An aerobic bacterial strain, designated R04, belonging to the genus Rhodococcus has been isolated and characerized by 16S rDNA analysis. The capability of this strain to degrade seven different polychlorinated biphenyls (CBs), 500 ppm 3-CB, 3,4-CB, 4,4-CB, 2,4,6-CB, 2,4,5-CB, 2,3,4,5-CB and 3,4,3,4-CB in liquid medium, was evaluated. After 5 days of incubation, the concentration of chloride increased to 0.35 mM in cultures containing 3-CB and R04, whereas in cultures with 3,4-CB, 2,3,4,5-CB or 3,4,3,4-CB plus R04 the chloride content increased to 0.1 mM. However, non-stoichiometric amounts of chloride were produced in cultures with R04 and 4,4-CB, 2,4,6-CB and 2,4,5-CB. The spectrum of supernatants from R04 grown on seven PCBs had a UV-visible (UV-VIS) absorption at 200–500 nm, characteristic of biphenyl-derived cleavage products. Gas-chromatographic (GC) analysis showed that R04 was able to transform 100% of 3-CB and 3,4-CB after 1 day of incubation, and 95% of 4,4-CB, 2,4,6-CB, 2,4,5-CB, 2,3,4,5-CB and 3,4,3,4-CB after 5 days of incubation. The position of the chlorine substituents on the rings strongly influenced the degradation of polychlorinated biphenyls (PCBs) and their intermediate metabolites by Rhodococcus sp. R04. The degradation of PCBs was further evaluated by monitoring intermediate metabolites of PCBs. 相似文献
7.
Claudia P. Spampinato Piotr Paneth Marion H. O'Leary Carlos S. Andreo 《Photosynthesis research》1991,28(2):69-76
Structural analogues of the NADP+ were studied as potential coenzymes and inhibitors for NADP+ dependent malic enzyme from Zea mays L. leaves. Results showed that 1, N6-etheno-nicotinamide adenine dinucleotide phosphate ( NADP+), 3-acetylpyridine-adenine dinucleotide phosphate (APADP+), nicotinamide-hypoxanthine dinucleotide phosphate (NHDP+) and -nicotinamide adenine dinucleotide 2: 3-cyclic monophosphate (23NADPc+) act as alternate coenzymes for the enzyme and that there is little variation in the values of the Michaelis constants and only a threefold variation in Vmax for the five nucleotides. On the other hand, thionicotinamide-adenine dinucleotide phosphate (SNADP+), 3-aminopyridine-adenine dinucleotide phosphate (AADP+), adenosine 2-monophosphate (2AMP) and adenosine 2: 3-cyclic monophosphate (23AMPc) were competitive inhibitors with respect to NADP+, while -nicotinamide adenine dinucleotide 3-phosphate (3NADP+), NAD+, adenosine 3-monophosphate (3AMP), adenosine 2: 5-cyclic monophosphate (25AMPc), 5AMP, 5ADP, 5ATP and adenosine act as non-competitive inhibitors. These results, together with results of semiempirical self-consistent field-molecular orbitals calculations, suggest that the 2-phosphate group is crucial for the nucleotide binding to the enzyme, whereas the charge density on the C4 atom of the pyridine ring is the major factor that governs the coenzyme activity.Abbreviations NADP+
1, N6-etheno-nicotinamide adenine dinucleotide phosphate
- NHDP+
nicotinamide-hypoxanthine dinucleotide phosphate
- APADP+
3-acetylpyridine-adenine dinucleotide phosphate
- SNADP+
thionicotinamide-adenine dinucleotide phosphate
- AADP+
3-aminopyridine-adenine dinucleotide phosphate
- 23NADPc+
-nicotinamide adenine dinucleotide 2: 3-cyclic monophosphate
- 3NADP+
-nicotinamide adenine dinucleotide 3-phosphate
- 2AMP
adenosine 2-monophosphate
- 3AMP
adenosine 3-monophosphate
- 23AMPc
adenosine 2: 3 monophosphate cyclic
- A
adenosine
- RuBP
ribulose 1,5-bisphosphate
- SCF-MO
Self-Consistent Field-Molecular Orbitals (method) 相似文献
8.
Wei Tong Wang Fumito Matsuura Hernan Nunez Norman Ledonne Jr. Betty Baltzer Charles C Sweeley 《Glycoconjugate journal》1984,1(1):17-35
Ten previously unreported oligosaccharides have been purified from the urines of human subjects using a combination of gel filtration, ion exchange, and thin-layer chromatographies. Their structures were determined by direct probe mass spectrometry, methylation analysis, and proton NMR spectroscopy of the permethylated oligosaccharide alditols.On the basis of composition, the oligosaccharides could be divided into three groups. Five oligosaccharides containing glycerol were characterized as glucosyl1-1glycerol; glucosyl1-1glycerol; galactosyl1-1glycerol; glucosyl-1-1(fucosyl-1-2)glycerol and/or fucosyl-1-1(glucosyl-1-2)glycerol; and glucosyl-1-1(galactosyl-1-2)glycerol or galactosyl-1-1(glucosyl-1-2)glycerol. Four inositol-containing oligosaccharides were characterized as galactosyl1 (fucosyl1)inositol,N-acetylgalactosaminyl1 (fucosyl1)inositol, fucosyl1-2galactosyl1 (N-acetylgalactosaminyl1)inositol and fucosyl1-2galactosyl1-4-N-acetylglucosaminyl1(N-acetylgalactosaminyl1)inositol. Finally, galactosyl1-3(fucosyl1-2)galactosyl1-6galactosyl1-4(fucosyl1-3)glucose, an oligosaccharide with glucose at its reducing end, was tentatively identified. The significance and possible origins of the carbohydrate structures are discussed. 相似文献
9.
2D NMR spectroscopy and J coupling constant analysis are applied to resolve the structure of two photoproducts of thymidylyl-(35)-thymidine. These products are cyclobutane type thymine dimers possessing the cis-syn (the predominant one) and trans-syn geometry. The cis-syn is formed in an ANTI-ANTI conformation about the N-glycosyl linkages and resembles the normal base-stacked configuration. The glycosidic conformation in solution of the 5 terminal fragment differs from the crystal in which the less common SYN conformation is observed. In this isomer only the sugar pucker of the 3 terminal fragment is changed substantially with respect to the dinucleotide. The trans-syn isomer is formed in a SYN-ANTI glycosidic conformation. In this isomer the sugar puckers of both deoxyribose rings are affected and a preference for a pure 2-endo conformation is observed.Abbreviations dTpdT
2-deoxythymidylyl-(35)-2-deoxythymidine
- dTp[]dT
cyclobutane type photodimers of dTpdT
- dTp- and dTp[]-
their 5' terminal fragments (fragment A)
- -pdT and-[]pdT
their 3 terminal fragments (fragment B)
- RP-HPLC
reversed-phase high-performance liquid chromatography
- COSY
two-dimensional correlated spectroscopy
- 2D NOE
two-dimensional nuclear Overhauser spectroscopy 相似文献
10.
A soluble protein that interacts with a range of cytokinins was extensively purified from wheat (Triticum aestivum L.) germ. This protein has a K
d
for kinetin of 2×10-7 M. The binding of kinetin to the protein is inhibited by low concentrations of synthetic and naturally-occurring cytokinins including N6-benzyladenine, N6-benzyladenosine, kinetin riboside, N6-dimethylallyladenine, N6-dimethylallyladenosine, zeatin, zeatin riboside, N6-dimethyladenine and N6-dimethyladenosine. Adenine, adenosine and several non-N6-substituted adenine derivatives were ineffective as inhibitors of kinetin binding. While N6-butyryl-3,5-cyclic AMP, N6,2-O-dibutyryl-3,5-cyclic AMP and 2,3-cyclic AMP inhibited binding of kinetin to the protein, 3,5-cyclic AMP was ineffective. The kinetin-binding protein is heat-labile and pronase-sensitive. Kinetin-binding activity exactly co-chromatographs with a single peak of carbohydrate and protein on gel-filtration and is displaced from concanavalin A-Sepharose 4B by -methylglucoside. On gel filtration, the kinetin-binding protein behaves as a soluble protein with an apparent molecular weight of 180,000 daltons. 相似文献
11.
Ishverlal P. Pankhania Alfred M. Spormann W. Allan Hamilton Rudolf K. Thauer 《Archives of microbiology》1988,150(1):26-31
Cell suspensions of Desulfovibrio vulgaris were found to catalyze, in the absence of sulfate, the complete conversion of 1 lactate to 1 acetate, 1 CO2, and 2 H2 (G0=-8.8 kJ/mol) and of 1 pyruvate to 1 acetate, 1 CO2, and 1 H2 (G0=-52 kJ/mol). Protonophores, the proton translocating ATPase inhibitor N,N-dicyclohexylcarbodiimide, and arsenate specifically inhibited H2 formation from lactate but not from pyruvate. The results suggest that lactate oxidation to pyruvate and H2 (G
0=+43.2 kJ/mol) is energy driven. 相似文献
12.
The rhesus macaque (Macaca mulatta) has become a popular animal model for several human infectious diseases, such as HIV (modeled by SIV infection), hepatitis, and malaria. Investigation of T-cell responses in experimental infectious diseases in rhesus macaques has benefited from an expanding understanding of the diversity of macaque MHC class I heavy chains and the restriction of antigen presentation by macaque class I molecules. Here we add to this understanding with the first nucleotide sequences of M. mulatta 2-microglobulin (2m) mRNA, including a portion of the 3-untranslated region (3UTR). In pairwise comparison, the 2m protein of M. mulatta differs from human and chimpanzee 2m by nine amino-acid substitutions (92% identity), and from Macaca fascicularis by one amino-acid difference in the signal peptide region (99% identity). Allelic variations were identified at one site in the 3UTR. A structural analysis of human or chimpanzee 2m and M. mulatta 2m suggests that the differences cluster in three solvent-exposed clusters and do not involve contacts with the class I heavy chain. We predict that human and macaque 2m should bind interchangeably with the class I heavy chains of the other species, and show that four M. mulatta class I alleles form cell surface complexes with human 2m. Further, we predict that W6/32 (a monoclonal antibody that recognizes a combined epitope of some class I heavy chains and 2m with a subtle species dependence) should bind similarly human or macaque class I molecules that are bound with 2m of either species, supported by evidence of recognition of both heterologous and homologous complexes of macaque class I heavy chains. Our findings contribute to the growing understanding of rhesus macaque histocompatibility antigens and antigen presentation, and to the phylogeny of 2m in primates.The nucleotide sequences data reported in this article have been submitted to GenBank under accession numbers AY349163 and AY445843 相似文献
13.
Teruo Yoshino Minobu Sadamitsu Megumi Minagawa Gerd Reuter Roland Schauer 《Glycoconjugate journal》1988,5(4):377-384
The preparation of benzyl 2,3,6,2,6-penta-O-benzyl--d-lactoside, which is a key intermediate for chemical synthesis of oligosaccharide components of glycosphingolipids, was achieved by an improved method. The 3-O-p-methoxybenzyl and 3-O-methyl derivatives were prepared from benzyl 2,3,6,2,6-penta-O-benzyl--d-lactoside through stannylation. By using benzyl -d-lactoside as starting material, benzyl 3-O-methyl-, 3-O-benzyl- and 3-O-p-methoxybenzyl--d-lactoside were regioselectively synthesized using the same procedure. 相似文献
14.
Vladimir N. Podust Tamara O. Korobeinicheva George A. Nevinsky Asja S. Levina Olga I. Lavrik 《Molecular biology reports》1990,14(4):247-249
Template-primer dependent inactivation of human DNA polymerase and Klenow fragment of E. coli DNA polymerase I by adenosine 2,3-riboepoxide 5-triphosphate was used for quantitative analysis of the Kd values for oligonucleotide primers of different length. The Kd values are smaller by a factor of 2.5 than the Km values for the same primers determined in the reaction of DNA polymerization in the case of DNA polymerase . The Kd and Km values are nearly the same for Klenow fragment. Such approach to the determination of Km/Kd ratio can likely be used for detailed quantitative analysis of DNA polymerases.Abbreviations epATP
adenosine 2,3-riboepoxide 5-triphosphate
- KF
Klenow fragment of E. coli DNA polymerase I
- Pol I
E. coli DNA polymerase I
- Pol
human placenta DNA polymerase 相似文献
15.
Folkert Reck Matthias Springer Ernst Meinjohanns Hans Paulsen Inka Brockhausen Harry Schachter 《Glycoconjugate journal》1995,12(6):747-754
UDP-GlcNAc:Man1-3R 1-2-N-acetylglucosaminyltransferase I (GlcNAc-T I; EC 2.4.1.101) catalyses the conversion of [Man1-6(Man1-3)Man1-6][Man1-3]Man-O-R to [Man1-6(Man1-3)Man1-6] [GlcNAc1-2Man1-3]Man-O-R (R=1-4GlcNAc1-4GlcNAc-Asn-X) and thereby controls the conversion of oligomannose to complex and hybrid asparagine-linked glycans (N-glycans). GlcNAc-T I also catalyses the conversion of Man1-6(Man1-3)Man-O-octyl to Man1-6(GlcNAc1-2Man1-3)Man-O-octyl. We have therefore tested a series of synthetic analogues of Man1-6(Man1-3)Man-O-octyl as substrates and inhibitors for rat liver GlcNAc-T I. The 2-deoxy and the 3-, 4- and 6-O-methyl derivatives are all good substrates confirming previous observations that the hydroxyl groups of the Man1-6 residue do not play major roles in the binding of substrate to enzyme. In contrast, all four hydroxyl groups on the Man1-3 residue are essential since the corresponding deoxy derivatives either do not bind (2- and 3-deoxy) or bind very poorly (4- and 6-deoxy) to the enzyme. The 2- and 3-O-methyl derivatives also do not bind to the enzyme. However, the 4-O-methyl derivative is a substrate (K
m
=2.6mm) and the 6-O-methyl compound is a competitive inhibitor (K
i=0.76mm). We have therefore synthesized various 4- and 6-O-alkyl derivatives, some with reactive groups attached to anO-pentyl spacer, and tested these compounds as reversible and irreversible inhibitors of GlcNAc-T I. The 6-O-(5-iodoacetamido-pentyl) compound is a specific time dependent inhibitor of the enzyme. Four other 6-O-alkyl compounds showed competitive inhibition while the remaining compounds showed little or no binding indicating that the electronic properties of the attachedO-pentyl groups influence binding.Abbreviations GlcNAc-T I
UDP-GlcNAc:Man1-3R 1-2-N-acetylglucosaminyltransferase I (EC 2.4.1.101)
- GlcNAc-T II
UDP-GlcNAc:Man1-6R 1-2-N-acetylglucosaminyltransferase II (EC 2.4.1.143)
- MES
2-(N-morpholino)ethane sulfonic acid monohydrate 相似文献
16.
W. W. Hanna 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,80(2):200-204
Summary Germ plasm from the A-genome of Pennisetum purpureum Schum. (AABB) of the secondary gene pool was transferred to cultivated pearl millet (AA) [P. glaucum (L.) R. Br.] by pollinating cytoplasmicnuclear male-sterile (cms) pearl millet with fertile allohexaploid pearl millet x P. purpureum hybrids (AAAABB). Certain allohexaploids used as pollinators on cms pearl millet resulted in 14-chromosome diploid pearl millet progenies. Three types of diploid pearl millet plants were produced in addition to the expected 28-chromosome AAAB-genome plants: (1) cms plants with only the A-genome, (2) cms plants with the A- and A-genomes, and (3) fertile plants with the A- and A-genomes. The latter group has allowed the utilization of genes for fertility restoration, stiff stalk, maturity, height, and morphological characteristics from the A-genome of P. purpureum in the pearl millet breeding program. Production of monoploid gametes by the allohexaploids appeared to be genetically controlled. 相似文献
17.
The molecular mechanism of membrane-associated reactions induced by auxin was investigated in membranes isolated from cultured cells of soybean (Glycine max L.). Auxins increased the activity of phospholipase A2 in microsomes isolated from suspensioncultured soybean cells. The reaction was measured as the accumulation of radioactive lysophosphatidylcholine hydrolyzed from radioactive phosphatidylcholine in membranes which had been prelabelled with [14-C]choline in vivo. Stimulation by auxin was detectable after 1 min and was auxin-specific in that weak auxins had little effect. Auxin concentrations as low as 2·10–8 M and up to 2·10+3 M -naphthaleneacetic acid already stimulated the phospholipase A2 activity. Guanosine and adenosine diphosphate at 100 M, if applied during homogenization of cells, completely abolished the stimulation of phospholipase A2 by auxin and, when applied after homogenization, had no effect. Guanosine and adenosine 5-O-thiotriphosphate, uridine 5-diphosphate, and uridine 5-triphosphate, all at 100 M, had no effect in either treatment, suggesting that only nucleotides entrapped in the vesicles could exert an effect. The effect of auxin on phospholipase A2 had an optimum at pH 5.5 and was abolished completely by an antibody against the membrane-associated auxin-binding protein from maize coleoptiles, applied after homogenization. This antibody recognized a 22-kDa polypeptide in highly purified plasma membranes from cultured soybean cells. This suggests a receptor function for this auxin-binding protein and a role for a cytosolic nucleotide-binding protein in the activation of phospholipase A2 by auxin. It is concluded that phospholipase A2 has a function in plant signal transduction.Abbreviations ABP
auxin-binding protein
- ATP S
adenosine 5-O-thiotriphosphate
- 2,4-D
2,4-dichlorophenoxyacetic acid
- GTP S
guanosine 5-O-(thiotriphosphate)
- IgG
immunoglobulin G
- LPC
lysophosphatidylcholine;
-
-NAA
, -naphthaleneacetic acid
- PLA2
phospholipase A2
We cordially acknowledge the gift of anti-ABP antibody by D. Klämbt and the help by H. Ordowski (both Botanisches Institut, Universität Bonn) with the immunoblotting experiments. This work was supported by the Deutsche Forschungsgemeinschaft. 相似文献
18.
Bennett T. Farmer II Luciano Müller Edward P. Nikonowicz Arthur Pardi 《Journal of biomolecular NMR》1994,4(1):129-133
Summary A set of three 3D (1H, 13C, 15N) triple-resonance correlation experiments has been designed to provide H1-H8 intraresidue sugar-to-base correlations in purines in an unambiguous and efficient manner. Together, the HsCsNb, HsCs(N)bCb, and HbNbCb experiments correlate the H1 sugar proton to the H8 proton of the attached base by means of the {H1, C1, N9, C8, H8} heteronuclear scalar coupling network. The assignment strategy presented here allows for unambiguous H1-H8 intraresidue correlations, provided that no two purines have both the same H1 and C1 chemical shifts and the same C8 and N9 chemical shifts. These experiments have yielded H1-H8 intraresidue sugar-to-base correlations for all five guanosines in the [13C, 15N] isotopically labeled RNA duplex r(GGCGCUUGCGUC)2. 相似文献
19.
Summary 2-Amino-2-deoxyuridine reacts efficiently with nucleoside 5-phosphorimidazolides in aqueous solution. The dinucleoside monophosphate analogues were obtained in yields exceeding 80% under conditions in which little reaction occurs with the natural nucleosides.In a similar way, the 5-phosphorimidazolide of 2-amino-2-deoxyuridine undergoes self-condensation in aqueous solution to give a complex mixture of oligomers.The phosphoramidate bond in the dinucleoside monophosphate analogues is stable for several days at room temperature and pH 7. The mechanisms of their hydrolysis under acidic and alkaline conditions are described.Abbreviations A
adenosine
- C
cytidine
- G
guanosine
- U
uridine
- T
thymidine
- UN
3
2-azido-2-deoxyuridine
- UNH
2
2-amino-2-deoxyuridine
- ImpA
adenosine 5-phosphorimidazolide
- ImpU
uridine 5-phosphorimidazolide
- ImpUN
3
2-azido-2-deoxyuridine 5-phosphorimidazolide
- ImpUNH
2
2-amino-2-deoxyuridine 5-phosphorimidazolide
- pA
adenosine 5-phosphate
- pU
uridine 5-phosphate
- pUN
3
2-azido-2-deoxyuridine 5-phosphate
- pUNH
2
2-amino-2-deoxyuridine 5-phosphate
- UpA
uridylyl-[35]-adenosine
- UpU
uridylyl-[35]-uridine
- UNpA
adenylyl-[52]-2-amino-2-deoxy-uridine
- UNpU
uridylyl-[52]-2-amino-2-deoxyuridine (pUN)n n=2,3,4 [25]-linked oligomers of pUNH
2 poly(A) polyadenylic acid
- Im
imidazole
- MeIm
l-methylimidazole 相似文献
20.
The filamentous cyanophyteNostoc muscorum A grew aseriately in light in a mineral salts (sugar-free) culture medium supplemented with adenosine 3:5-cyclic-monophosphate or N6, O2-dibutyryl adenosine 3:5-cyclic-monophosphate (1 mM). The aseriate morphology thus formed in the light on the 10th day following inoculation was similar to that formed in the dark after 20–30 days growth in cAMP-free medium containing glucose or sucrose. Inoculum previously grown in sucrose- or glucose-containing medium displayed aseriate morphology with lesser proliferation of coccoid cells as compared to inoculum grown in the absence of glucose or sucrose. cGMP, ADP, AMP and inhibitors of phosphodiesterase (theophylline and caffeine) did not have any effect on the persistence of aseriate morphology. However they stimulated cell division at the aseriate stage and delayed the release of hormogonia.Abbreviations cAMP
adenosine 3:5-cyclic-monophosphate
- db cAMP
N6, O2-dibutyryl adenosine 3:5-cyclic-monophosphate
- cGMP
guanosine 3:5-cyclic-monophosphate
- ATP
adenosine 5-triphosphate
- ADP
adenosine5-diphosphate
- AMP
adenosine 5-monophosphate 相似文献