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1.
Nucleotide sequence of the PR-1 gene of Nicotiana tabacum 总被引:7,自引:0,他引:7
M Ohshima M Matsuoka N Yamamoto Y Tanaka Y Kano-Murakami Y Ozeki A Kato N Harada Y Ohashi 《FEBS letters》1987,225(1-2):243-246
A gene encoding one of the pathogenesis-related proteins, PR1a, and two related pseudogenes were isolated from Nicotiana tabacum. The cloned PR1a gene (pPR-gamma) and one of the pseudogenes (pPR-alpha) were sequenced and found to have similar structures. The sequence of pPR-gamma was quite similar to that of the cDNA clone of PR1a. The plasmid pPR-gamma did not contain an intron and had a typical promoter sequence in the 5'-flanking region. 相似文献
2.
Yuichi Fujita Yasuhiro Takahashi Takayuki Kohchi Haruo Ozeki Kanji Ohyama Hiroshi Matsubara 《Plant molecular biology》1989,13(5):551-561
The frxC gene, one of the unidentified open reading frames present in liverwort chloroplast DNA, shows significant homology with the nifH genes coding for the Fe protein, a component of the nitrogenase complex (Ohyama et al., 1986, Nature 322: 572–574). A truncated form of the frxC gene was designed to be over-expressed in Escherichia coli and an antibody against this protein was prepared using the purified product as an antigen. This antibody reacted with a protein in the soluble fraction of liverwort chloroplasts, which had an apparent molecular weight of 31 000, as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, in good agreement with a putative molecular weight of 31945 deduced from the DNA sequence of the frxC gene. In a competitive inhibition experiment, the antigenicity of this protein was indicated to be similar to that of the over-expressed protein in E. coli. Therefore, we concluded that the frxC gene was expressed in liverwort chloroplasts and that its product existed in a soluble form. The molecular weight of the frxC protein was approximately 67 000, as estimated by gel filtration chromatography, indicating that the frxC protein may exist as a dimer of two identical polypeptides analogous to the Fe protein of nitrogenase. The results obtained from affinity chromatography supported the possibility that the frxC protein, which possesses a ATP-binding sequence in its N-terminal region that is conserved among various other ATP-binding proteins, has the ability to bind ATP. 相似文献
3.
Effects of the nature and orientation of a side chain in cyclic octapeptides on Ca2+ transport were examined by using cyclo[L-Lys(Z)-Sar-L-Leu-Sar]2 (C8-L), cyclo[L-Lys(Z)-Sar]4 (C8KS), and their diastereomer cyclic octapeptides, cyclo[L-Lys(Z)-Sar-D-Leu-Sar]2 (C8-D) and cyclo[L-Lys(Z)-Sar-D-Lys(Z)-Sar]2 (C8Kk). All these cyclic octapeptides were found to take a single conformation in CDCl3, and the conformation was C2-symmetric for C8-L and C8-D, and C4-symmetric for C8KS and C8Kk. They formed a complex with Ca2+. Upon complexation, C8KS accompanied isomerization of peptide bonds, but C8-D retained the arrangement of peptide bonds. The amount of Ca2+ extracted from an aqueous solution to a chloroform solution by all L cyclic octapeptide C8-L or C8KS was about twice that of Na+, but 6-8-fold smaller than that by C8-D or C8Kk including D units. These cyclic octapeptides were capable of transporting Ca2+ through a lipid membrane above the phase transition temperature, and the transport rate decreased in the order of C8Kk-C8KS greater than C8-D greater than C8-L. 相似文献
4.
A comparative study on immunosuppressive effects of cyclosporin A and FK 506 on peripheral blood lymphocytes in dogs 总被引:1,自引:0,他引:1
Kyoichi Takaori Yoshinori Nio Kazutomo Inoue Thein Tun Manaba Fukumoto Tohru Hashida Masato Yasuhara Ryohei Hori Takayoshi Tobe 《Biotherapy》1992,4(2):129-137
Immunosuppressive effects of cyclosporin A (CsA) and FK 506 (FK) on peripheral blood lymphocytes were studied in dogs in respect to mixed lymphocyte reaction, proliferative responses to recombinant interleukin-2 (rIL-2), phytohemagglutinin (PHA) and concanavalin-A (Con-A); phenotypes of OKIa1, CD3, CD8 and surface IgM; cytotoxic activity against xenogeneic tumor cells. CsA (2.0 or 5.0 mg/kg, intravenously) or FK (0.16 mg/kg, intramuscularly) was given to mongrel dogs every morning for serial 21 days. The blood concentrations of CsA, measured as trough levels by fluorescence polarization method, ranged from 37 to 350 ng/ml in dogs administered at 2.0 mg/kg and from 170 to 894 ng/ml in dogs administered at 5.0 mg/kg during treatment, respectively. In dogs treated with FK at a dose of 0.16 mg/kg, the drug concentrations in the plasma during treatment ranged from 0.16 to 1.8 ng/ml. Mixed lymphocyte reaction and proliferative responses to rIL-2, PHA and Con-A, which were declined by CsA, were not affected by FK. In contrast, the proportion of OKIa1+ cells was not affected by CsA, whereas FK decreased the proportion of OKIa1+ cells progressively during the course of treatment. Cytotoxic activity was suppressed by both CsA and FK. These results possibly indicate that CsA and FK exert their immunosuppressive effects via different mechanisms. 相似文献
5.
Mischarging mutants of Su+2 glutamine tRNA in E. coli. II. Amino acid specificities of the mutant tRNAs 总被引:1,自引:0,他引:1
F Yamao H Inokuchi J Normanly J Abelson H Ozeki 《The Japanese Journal of Genetics》1988,63(3):251-258
Among the mischarging mutants isolated from strains with Su+2 glutamine tRNA, two double-mutants, A37A29 and A37C38, have been suggested to insert tryptophan at the UAG amber mutation site as determined by the suppression patterns of a set of tester mutants of bacteria and phages (Yamao et al., 1988). In this paper, we screened temperature sensitive mutants of E. coli in which the mischarging suppression was abolished even at the permissive temperature. Four such mutants were obtained and they were identified as the mutants of a structural gene for tryptophanyl-tRNA synthetase (trpS). Authentic trpS mutations, such as trpS5 or trpS18, also restricted the mischarging suppression. These results strongly support the previous prediction that the mutant tRNAs of Su+2, A37A29 and A37C38, are capable of interacting with tryptophanyl-tRNA synthetase and being misaminoacylated with tryptophan in vivo. However, in an assay to determine the specificity of the mutant glutamin tRNAs, we detected predominantly glutamine, but not any other amino acid, being inserted at an amber codon in vivo to any significant degree. We conclude that the mutant tRNAs still accept mostly glutamine, but can accept tryptophan in an extent for mischarging suppression. Since the amber suppressors of Su+7 tryptophan tRNA and the mischarging mutants of Su+3 tyrosine tRNA are charged with glutamine, structural similarity among the tRNAs for glutamine, tryptophan and tyrosine is discussed. 相似文献
6.
K Ohuchi M Watanabe N Hirasawa S Tsurufuji T Ozeki H Fujiki 《Biochimica et biophysica acta》1988,971(1):85-91
Rat peritoneal macrophages were prelabeled with [3H]arachidonic acid. The release of radioactivity into the medium was increased by treatment with TPA-type tumor promoters, such as TPA, teleocidin and aplysiatoxin, and the non-TPA-type tumor promoter, thapsigargin. Gossypol, at concentrations of 3 and 10 microM, inhibited the release of radioactivity stimulated by both types of tumor promoter, although the mechanism of stimulation of arachidonic acid metabolism is different in the two types of tumor promoter. Stimulation of prostaglandin E2 production by these tumor promoters was also inhibited by treatment with gossypol. Calcium ionophore A23187-stimulated release of radioactivity and prostaglandin E2 production were also inhibited by gossypol treatment. The mechanism of inhibition by gossypol of prostaglandin E2 production is discussed. 相似文献
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10.
Primary structure of hemorrhagic protein, HR2a, isolated from the venom of Trimeresurus flavoviridis 总被引:5,自引:0,他引:5
T Miyata H Takeya Y Ozeki M Arakawa F Tokunaga S Iwanaga T Omori-Satoh 《Journal of biochemistry》1989,105(5):847-853
The complete amino acid sequence and disulfide bridge location of HR2a, one of the hemorrhagic proteins isolated from the snake venom of Trimeresurus flavoviridis, have been determined by analysis of peptides derived from digests with cyanogen bromide, lysyl endopeptidase, trypsin, and Staphylococcus aureus V8 protease. Peptides were purified by gel filtration followed by reversed-phase HPLC. HR2a has the amino-terminal sequence of less than Glu-Gln-Arg- and consists of a total of 202 residues with a calculated molecular weight of 23,015. Sequence analysis indicates the presence of another isoform which lacks the amino-terminal residue, making 201 amino acid residues with a molecular weight of 22,887. Three disulfide bridges of HR2a link Cys-118 to Cys-197, Cys-159 to Cys-181, and Cys-161 to Cys-164. HR2a contains a segment which is similar to the zinc-chelating sequences found in thermolysin and several mammalian metalloproteinases, suggesting that HR2a is a metalloproteinase with limited substrate specificity. However, there is no other significant sequence homology with thermolysin except for the zinc-ligand region. 相似文献