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Keisuke Ueda Chieko Kimura-Sakiyama Tomoki Aihara Masao Miki Toshiaki Arata 《Biophysical journal》2013
To identify the interaction sites of Tm, we measured the rotational motion of a spin-label covalently bound to the side chain of a cysteine that was genetically incorporated into rabbit skeletal muscle tropomyosin (Tm) at positions 13, 36, 146, 160, 174, 190, 209, 230, 271, or 279. Most of the Tm residues were immobilized on actin filaments with myosin-S1 bound to them. The residues in the mid-portion of Tm, namely, 146, 174, 190, 209, and 230, were mobilized when the troponin (Tn) complex bound to the actin-Tm-S1 filaments. The addition of Ca2+ ions partially reversed the Tn-induced mobilization. In contrast, residues at the joint region of Tm, 13, 36, 271, and 279 were unchanged or oppositely changed. All of these changes were detected using a maleimide spin label and less obviously using a methanesulfonate label. These results indicated that Tm was fixed on thin filaments with myosin bound to them, although a small change in the flexibility of the side chains of Tm residues, presumably interfaced with Tn, actin and myosin, was induced by the binding of Tn and Ca2+. These findings suggest that even in the myosin-bound (open) state, Ca2+ may regulate actomyosin contractile properties via Tm. 相似文献
95.
Hiroshi Fukamachi Shinko Kato Makoto Asashima Masao Ichinose Yasuhito Yuasa 《Development, growth & differentiation》2013,55(9):786-791
The importance of epithelial–mesenchymal interaction on the development of gastro‐intestinal (GI) organs has been repeatedly reported, but its molecular mechanism has not been fully understood though several factors including hepatocyte growth factor and endothelin‐3 have been shown to mediate it. Activins have been demonstrated to play important roles in the regulation of organogenesis in vertebrates, but their roles in the regulation of growth and differentiation of GI organs remain to be solved. In the present study, we examined expression of activins in developing rat GI tract, and found that inhibin bA encoding activin A was specifically expressed by GI mesenchymes, while inhibin bB encoding activin B was expressed by both epithelial and mesenchymal components. We then examined the effect of activin A on the growth of fetal rat GI epithelial cells in primary culture. We found that activin A inhibited the growth of forestomach and glandular stomach epithelial cells while it stimulated the growth of colonic epithelial cells. These results suggest that activin A secreted from GI mesenchymes region‐specifically regulates the growth of attaching epithelial cells. We thus conclude that activin A mediates epithelial‐mesenchymal interaction in the developing GI tract. 相似文献
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Michiyo Takahara Haruka Sakaue Yukiko Onishi Marifu Yamagishi Yuichiro Kida Masao Sakaguchi 《Biochemical and biophysical research communications》2013,430(2):567-572
Nascent chain release from membrane-bound ribosomes by the termination codon was investigated using a cell-free translation system from rabbit supplemented with rough microsomal membrane vesicles. Chain release was extremely slow when mRNA ended with only the termination codon. Tail extension after the termination codon enhanced the release of the nascent chain. Release reached plateau levels with tail extension of 10 bases. This requirement was observed with all termination codons: TAA, TGA and TAG. Rapid release was also achieved by puromycin even in the absence of the extension. Efficient translation termination cannot be achieved in the presence of only a termination codon on the mRNA. Tail extension might be required for correct positioning of the termination codon in the ribosome and/or efficient recognition by release factors. 相似文献
98.
Tsukasa Mizuhara Shinya Oishi Hiroaki Ohno Kazuya Shimura Masao Matsuoka Nobutaka Fujii 《Bioorganic & medicinal chemistry》2013,21(7):2079-2087
To investigate the mechanism of action of the potent antiviral compound PD 404182, three novel photoaffinity probes equipped with a biotin or alkyne indicator were designed and synthesized based on previous structure–activity relationship studies. These probes retained the potent anti-HIV activity of the original pyrimidobenzothiazine derivatives. In photoaffinity labeling studies using HIV-1-infected H9 cells (H9IIIB), eight potential proteins were observed to bind PD 404182. 相似文献
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Kenji Seiwa Yoshiko Miwa Shigetoshi Akasaka Hiroshi Kanno Mizuki Tomita Tomoyuki Saitoh Naoto Ueno Megumi Kimura Yoichi Hasegawa Miki Konno Kazuhiko Masaka 《Ecological Research》2013,28(1):29-41
To evaluate the extent to which landslides affect community dynamics and consequent species diversity in a beech-dominated forest, differences in the composition and size structure of tree species were compared between landslide and adjacent stable (control) stands. Demography and changes in size were compared between the two stands over a 5-year period about 60 years after a landslide. In the control stand, replacement occurred even amongst late-successional species, with beech (Fagus crenata)—the most dominant species—increasing in relative abundance. In the landslide stand, very few large individuals of late-successional species occurred, whereas large individuals of early-successional species occurred only in the landslide stand. The traits indicate that the landslide strongly facilitated species diversity, not only by reducing the dominance of late-successional species, but also by promoting recruitment of early-successional species. However, new recruitment of early-successional species was inhibited in the landslide stand, although we observed succeeding regeneration and subsequent population growth of late-successional species there. As a result, the relative dominance of late-successional species increased with succession after the landslide, thus decreasing future species diversity. In beech-dominant forest landscapes in Japan that include communities with different developmental stages, the mosaic of serial stages may facilitate species diversity after a landslide. 相似文献
100.
Masao Fujimaki Makoto Tajima Teruyo Matsumoto 《Bioscience, biotechnology, and biochemistry》2013,77(10):1228-1231
The free amino acids of potatoes irradiated with the doses of 7,000, 15,000 and 30,000 rad were determined by ion-exchange chromatography.After 15 days storage following irradiation, it was shown that the concentration of asparatic acid, proline and aliphatic amino acids increased with increasing irradiation doses, while that of basic amino acids and glutamic acid especially decreased. However, after 105 days of storage, the similarity of the free amino acid content of irradiated potatoes to that of non-irradiated and non-stored potatoes was observed.On the concentration of protein-bound amino acids, there were no significant differences between non-irradiated and 15,000 rad irradiated potatoes. 相似文献