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71.
X-ray diffraction studies of enkephalins. Crystal structure of [(4''-bromo) Phe4,Leu5]enkephalin. 总被引:3,自引:1,他引:2
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T Ishida M Kenmotsu Y Mino M Inoue T Fujiwara K Tomita T Kimura S Sakakibara 《The Biochemical journal》1984,218(3):677-689
In order to investigate the structure-activity relationship of [Leu5]- and [Met5]enkephalins, [(4'-bromo)Phe4, Leu5]-, [(4'-bromo)Phe4, Met5]- and [Met5] enkephalins were synthesized and crystallized. The crystal structure of [(4'-bromo) Phe4, Leu5]- enkephalin was determined by X-ray diffraction method using the heavy atom method and refined to R = 0.092 by the least-squares method. The molecule in this crystal took essentially the same type I' beta-turn conformation found in [Leu5]enkephalin [Smith & Griffin (1978) Science 199, 1214-1216). On the other hand, the preliminary three-dimensional Patterson analyses showed that the most probable conformations of [(4'-bromo)Phe4,Met5]- and [Met5]enkephalins are both the dimeric extended forms. Based on these insights, the biologically active conformation of enkephalin was discussed in relation to the mu- and delta-receptors. 相似文献
72.
A new germacranolide isolated from M. sieboldii was shown to be 15-acetoxycostunolide by spectroscopic and chemical methods. 1H NMR spin decoupling and NOE experiments in the presence of a lanthanide shift reagent were used for structure elucidation. 相似文献
73.
Toshimasa Ishida Ken-Ichi Tomita Masatoshi Inoue 《Archives of biochemistry and biophysics》1980,200(2):492-502
The crystal and molecular structures of the title complex has been determined by X-ray diffraction methods, as a model for tryptophan residues in protein-pyridine coenzyme interactions. The structure was solved by direct methods and was refined by standard methods (final R = 0.073). The light-green crystals consist of alternate layers of indole-3-acetic acid and 1-methyl-3-carbamoylpyridinium molecules piled up to the c-direction, and are stabilized by the crystal water participating in hydrogen bonds in the a- and b-directions. The parallel stackings and interplanar spacing distances between indole and pyridinium rings strongly suggest a II–II1 charge transfer from the indole ring to the lowest unoccupied orbital of the pyridinium ring in the ground state. Furthermore, this crystal structure provides evidence that quaternization of the N1 position enhances electron-acceptor properties of pyridine. On the other hand, the proton magnetic resonance spectra suggest that the stacking mode between both rings in solution is very similar to the one observed in the crystal structure. 相似文献
74.
Giuliano Armando E. Irie Reiko F. Morton Donald L. 《Cancer immunology, immunotherapy : CII》1981,10(4):243-249
Summary The oncofetal antigen-I (OFA-I) has been defined as an immunogenic antigen that is expressed on human cancer cells and is cross reactive with fetal brain tissue. Quantitative variations in the expression of OFA-I among different cultured melanoma cell lines were determined by absorption techniques based on functionally monospecific anti-OFA-I serum. Allo-antibodies were removed by absorption with lymphoblasts autologous to an OFA-I-positive target cell. Functional monospecificity toward OFA-I was confirmed by complete absorption with a specimen of fetal brain but not by liver from the same fetus.Of 14 melanoma cell lines tested, two did not express OFA-I, whereas 12 expressed the antigen to varying degrees. Five of the cell lines were highly antigenic, and serum absorbed with 5×105 of any of these cell lines could reduce the anti-OFA-I titer (1 : 96) at least four-fold. OFA-I was detected on biopsied melanomas autologous to the antigenic cultured cells. The ability to select highly antigenic cell lines could be useful in further attempts to characterize OFA-I and to monitor tumor immunity in vitro. Antigenic cell lines may improve the response of patients treated in trials of immunotherapy. 相似文献
75.
To investigate the dynamics of membrane processes that may be integral components of specific transmembrane signaling events we have synthesized several novel paramagnetic probes and their photoreactive counterparts. The structure of these probes was designed to (1) restrict “flipping” across the membrane bilayer; (2) contain paramagnetic or photoreactive moieties that could be placed at specific depths within the bilayer; (3) provide information about membrane structure as well as dynamics of protein movement; and (4) in the case of the photoreactive probes, be of high specific radioactivity. The molecules described in this paper consist of amino acid, dipeptide, or carbohydrate groups attached to arylazide- or nitroxide-bearing fatty acids. The synthesis and initial characterization of these membrane probes is described. 相似文献
76.
77.
Toshihiko Ubuka Masahiro Kinuta Reiko Akagi Shozo Kiguchi Miyabi Azumi 《Analytical biochemistry》1982,126(2):273-277
A procedure for the simultaneous preparation of S-sulfo-l-cysteine and l-alanine 3-sulfinic acid is described. The method is based on the quantitative reaction between sulfite and S-(2-amino-2-carboxyethylsulfonyl)-l-cysteine. The yield was 95% for S-sulfo-l-cysteine and 91% for l-alanine 3-sulfinic acid. The reaction was also applied to the quantitative determination of sulfite in biological materials. In this procedure, sulfite reacts with S-(2-amino-2-carboxyethylsulfonyl)-l-cysteine. Separation of the reaction product, S-sulfo-l-cysteine, is done by ion-exchange fractionation, and it is determined with acid ninhydrin reagent 2 (M. K. Gaitonde, 1967, Biochem. J.104, 627–663). The recovery was 96.8 ± 0.3%. 相似文献
78.
Synthesis of two ω-aldehydoalkyl 1-thioglycosides of d-glucopyranose and of d-galactopyranose is described. 3-Oxopropyl and 2-oxoethyl 1-thioglycosides were prepared by treating a tetra-O-acetyl-1-thioaldose with either acrolein or 2-bromoacetaldehyde, followed by O-deacetylation under mild conditions. These ω-aldehydoalkyl 1-thioglycosides were successfully attached to bovine serum albumin (BSA) by reductive alkylation as described previously. With the 3-oxopropyl 1-thioglycosides, much higher levels of sugar attachment (e.g., ~80 mol of sugar per mol of BSA) were attained than hitherto possible with any sugar derivative tested. 相似文献
79.
H Ueda H Maruyama M Doi M Inoue T Ishida H Morioka T Tanaka S Nishikawa S Uesugi 《Journal of biochemistry》1991,109(6):882-889
An artificial gene coding for the human cap binding protein (hCBP: human IF-4E) was chemically synthesized and expressed in Escherichia coli under the control of a trp promoter. The DNA duplex of 662 bp was designed and constructed from 44 oligodeoxynucleotide fragments of typically 30 nucleotides in length. Although the hCBP gene was not directly expressed in E. coli HB101, we succeeded in its high-level expression as a fusion protein connected with a portion of human growth hormone through a tetradecapeptide (Asp-Asp-Pro-Pro-Thr-Val-Glu-Leu-Gln-Gly-Leu-Val-Pro-Arg) that contains the recognition sequence for a site-specific protease alpha-thrombin. Upon induction with 3-indoleacrylic acid, the fusion protein accumulated with a yield of about 20% of the total proteins of the host cell. Upon the treatment of the fusion protein with alpha-thrombin, which recognizes the sequence "Val-Pro-Arg," specific proteolysis at the fused junction occurred efficiently. In this system, nonspecific digestion by alpha-thrombin was not marked. About 15 mg of recombinant hCBP was obtained from a 1-liter culture. Association constants between the recombinant hCBP and mRNA cap structure analogues were determined by fluorescence spectroscopy. The values obtained for the m7GpppA, m7GTP, and m7GMP were almost the same as those reported for the IF-4E isolated from human erythrocyte cells.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
80.
A Yamamoto T Kaji K Tomoo T Ishida M Inoue M Murata K Kitamura 《Journal of molecular biology》1992,227(3):942-944
Cathepsin B from bovine spleen has been purified and crystallized as a complex with a specific inhibitor CA074 [N-(L-3-trans-propylcarbamoyloxirane-2-carbonyl)-L- isoleucyl-L-proline], using the hanging-drop method. The complex crystals obtained from 50 mM-citrate buffer (pH 3.5) belong to the tetragonal space group P4(1) (or P4(3)) with a = 73.06 A and c = 141.59 A, and diffract beyond 2.2 A resolution. There are two complex molecules per asymmetric unit giving a packing density of 3.37 A3/Da and indicating a high solvent content of 63.5%. 相似文献