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1.
Kai-xun Huang You-xiang An Ze-xian Chen Hui-bi Xu 《Biological trace element research》2001,82(1-3):247-257
Selenium-containing tRNA was discovered in germinating barley for the first time with the 75Se isotopic tracer technique; therefore, this technique was used to study the effect of different concentrations of selenium
and sulfur in the medium on the content of selenium-containing tRNA in germinating barley. Se-containing tRNAs and its hydrolysates
were isolated, purified, and characterized by means of column chromatography, ion-exchange chromatography, high-performance
liquid chromatography, and the ultraviolet-visible spectrum. The results show that the amount of selenium in tRNA is almost
unaffected by the sulfuric content in the medium, and the pathway for selenium and sulfur to enter tRNA might not be exactly
the same. Selenium exists within tRNA in the form of 5-methylamine methyl-2-selenouridine, just as it does within a microorganism
tRNA. 相似文献
2.
From wheat embryos, tRNA nucleotidyltransferase (EC 2.7.7.25) was isolated. By chromatography on Sepharose 6B, DEAE-cellulose and affinity chromatography on tRNA-hydrazyl-Sepharose 4B, 7000-fold purification of the enzyme was achieved. The enzyme required for its activity Mg2+ or Mn2+ ion. ATP inhibited incorporation of CMP from CTP into lupin tRNA, and CTP acted as a competitive inhibitor of AMP incorporation from ATP. The regulatory role of ATP in incorporation of terminal CMP into tRNA is discussed. The incorporation of terminal CMP into tRNA deprived of terminal CCA or CA, was also studied. 相似文献
3.
The sequence of phenylalanine tRNA from E. coli 总被引:28,自引:0,他引:28
4.
Isolation of cytokinins from tRNA 总被引:29,自引:0,他引:29
D J Armstrong W J Burrows P K Evans F Skoog 《Biochemical and biophysical research communications》1969,37(3):451-456
5.
The nucleotide sequence of tRNA(Phe) from Bacillussubtilis W 23 has been determined using (32)P labeled tRNA. This is the second B. subtilis tRNA so far reported. The nucleotide sequence was found to be pG-G-C-U-C-G-G-U-A-G-C-U-C-A-G-U-D-G-G-D-A-G-A-G-C-A-A-C-G-G-A-C-U-Gm-A-A- ms(2)i(6)A-A-psi-C-C-G-U-G-U-m(7)G-U-C-G-G-C-G-G-T-psi- C-G-A-U-U-C-C-G-U-C-C-C-G-A-G-C-C-A-C-C-A(OH).Images 相似文献
6.
The energy-dependent transport of phenylalanine into isolated vacuoles of barley (Hordeum vulgare L.) mesophyll protoplasts has been studied by silicone-layer floatation filtering. The uptake of this aromatic amino acid into the vacuolar compartment is markedly increased by MgATP, showing saturation kinetics; the K
m values were 0.5 mM for MgATP and 1.2 mM for phenylalanine. V
max for phenylalanine transport was estimated to 140 nmol phenylalanine·(mg·Chl)-1·h-1. The transport shows a distinct pH optimum at 7.3 and is markedly inhibited by 40 mM nitrate. Azide (1 mM) and vanadate (400 M) had no or little effect on rates of transport while p-fluorophenylalanine seemed to be an effective inhibitor, indicating a possible competition at an amino-acid carrier. Ionophores such as valinomycin, nigericin or gramicidin were strong inhibitors of phenylalanine transport, indicating that this process is coupled to both the transmembrane pH gradient (pH) and the transmembrane potential ().Abbreviations and symbols BSA
bovine serum albumin
- Chl
chlorophyll
- Hepes
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- pH
transmembrane pH gradient
-
transmembrane potential 相似文献
7.
M Sprinzl 《European journal of biochemistry》1974,49(3):595-605
8.
9.
Affinity chromatography of phenylalanine:tRNA ligase 总被引:1,自引:0,他引:1
10.
The complete nucleotide sequence of tRNAPhe and 5S RNA from the photosynthetic bacterium Rhodospirillum rubrum has been elucidated. A combination of in vitro and in vivo labelling techniques was used. The tRNAPhe sequence is 76 nucleotides long, 7 of which are modified. The primary structure is typically prokaryotic and is most similar to the tRNAPhe of Escherichia coli and Anacystis nidulans (14 differences of 76 positions). The 5S ribosomal RNA sequence is 120 nucleotides long and again typical of other prokaryotic 5S RNAs. The invariable GAAC sequence is found starting at position 45. When aligned with other prokaryotic 5S RNA sequences, a surprising amount of nucleotide substitution is noted in the prokaryotic loop region of the R. rubrum 5S RNA. However, nucleotide complementarity is maintained reinforcing the hypothesis that this loop is an important aspect of prokaryotic 5S RNA secondary structure. The 5S and tRNAPhe are the first complete RNA sequences available from the photosynthetic bacteria. 相似文献
11.
12.
Spectroscopic properties of oligonucleotides excised from the anticodon region of phenylalanine tRNA from yeast 总被引:6,自引:0,他引:6
Ultraviolet absorption and static fluorescence properties of hexanucleotide (Gm-A-A-Y-A-ψp) and a dodecanucleotide (A-Cm-U-Gm-A-A-Y-A-ψ-m5C-U-Gp) excised from the anticodon region of phenylalanine tRNA from yeast have been studied with respect to temperature, pH, ionic strength, and Mg2+ concentration. At low temperature these oligomers have a largely stacked structure. Only the melting data of the dodecanucleotide in absence of Mg2+ fit a two-state model. From the different melting behavior of the oligonucleotides after excision of base Y, a rodlike structure of the hexanucleotide produced by stacking interactions can be concluded. The Y fluorescence increase produced by Mg2+ has been used to evaluate the binding equilibria between Mg2+ and the oligonucleotides. One strong binding site per oligonucleotide and a greater number of weak binding sites have been found. The fluorescence of the free base Y is not influenced by Mg2+. The dodecanucleotide enhances the ethidium fluorescence to the same extent as tRNAPhe and produces comparable shifts in the excitation and emission spectra. Therefore a double helical structure for this oligomer under the assay conditions is suggested. Only weak binding of ethidium to the hexanucleotide is observed, indicating that intercalation of the dye into its structure is not favored. The data show the decisive role of the nucleobase Y in maintaining a rigid stacked structure of the anticodon nucleotides. This structure is stabilized by high ionic strength, Mg2+, and ethidium. 相似文献
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16.
Isolation and partial characterization of wheat-germ-agglutinin-like lectins from rye (Secale cereale) and barley (Hordeum vulgare) embryos 总被引:6,自引:1,他引:6 下载免费PDF全文
Lectins have been isolated from embryos of Secale cereale (rye) and Hordeum vulgare (barley) by affinity chromatography on immobilized N-acetylglucosamine. Both lectins are dimeric proteins of two identical subunits of mol.wt. 18000. They resemble strongly wheat-germ agglutinin with respect to their chemical, physical, biological and immunological properties. 相似文献
17.
The phenylalanine tRNA from the cytoplasm of Neurospora crassa has been purified and sequenced. The sequence is: pGCGGGUUUAm2GCUCA (N) GDDGGGAGAGCm22GpsiCAGACmUGmAAYApsim5CUGAAGm7GDm5CGUGUGTpsiCGm1AUCCACACAAACCGCACCAOH. Both in the nature of modified nucleotides which are present in this tRNA and in the overall sequence, this tRNA resembles more closely phenylalanine tRNAs of eukaryotic cytoplasm than those of prokaryotes. The sequence of this tRNA differs from those of the corresponding tRNAs of wheat germ and yeast by only 6 and 7 nucleotides respectively out of 76 nucleotides.U 相似文献
18.
Andrzej Podstolski 《Physiologia plantarum》1981,52(4):407-410
Isolated chloroplasts of barley seedlings ( Hordeum vulgare L.) when kept in light, released a soluble, thermostable factor that inhibited phenylalanine ammonia-lyase (PAL) in vitro . Highest inhibition was found when chloroplasts were suspended in PAL-containing extract and kept in light. Efficiency of PAL activity inhibition did not depend greatly on the type of medium used for chloroplast isolation, nor on the composition of buffer in which the enzymatic activity was measured. It is proposed that in green tissues chloroplasts may participate in regulation of cytoplasmic PAL activity. 相似文献
19.
The nucleotide sequence of Mycoplasma sp. (Kid) phenylalanine tRNA was determined to be pG-G-U-C-G-U-G-U-A-G-C-U-C-A-G-U-C-G-G-D-A-G-A-G-C-A-G-C- A-G-A-C-U-G-A-A-m(1)G-C-Psi-C-U-G-C-G-U-m(7)G-U-C-G-G-C-G-G-U-Psi-C-A-A-U-U-C-C-G-U-C-C-A-C-G-A-C-C-A-C-C-A(OH). It is characterized by the absence of ribothymidine and the presence of only few modified nucleotides. 相似文献