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121.
Kazuki?OkochiEmail author Tetsu?Mieno Kazuhiko?Kondo Sunao?Hasegawa Kosuke?Kurosawa 《Origins of life and evolution of the biosphere》2015,45(1-2):195-205
In order to investigate impact production of carbonaceous products by asteroids on Titan and other satellites and planets, simulation experiments were carried out using a 2-stage light gas gun. A small polycarbonate or metal bullet with about 6.5 km/s was injected into a pressurized target chamber filled with 1 atm of nitrogen gas, to collide with a ice + iron target or an iron target or a ice + hexane + iron target. After the impact, black soot including fine particles was deposited on the chamber wall. The soot was carefully collected and analyzed by High Performance Liquid Chromatography (HPLC), Fourier Transform Infrared Spectroscopy (FT-IR), and Laser Desorption Time-of-Flight Mass Spectrometry (LD-ToF-MS). As a result of the HPLC analysis, about 0.04–8 pmol of glycine, and a lesser amount of alanine were found in the samples when the ice + hexane + iron target was used. In case of the ice + iron target and the iron target, less amino acids were produced. The identification of the amino acids was also supported by FTIR and LD-ToF-MS analysis. 相似文献
122.
Stereochemical conversion of C3‐vinyl group to 1‐hydroxyethyl group in bacteriochlorophyll c by the hydratases BchF and BchV: adaptation of green sulfur bacteria to limited‐light environments 下载免费PDF全文
123.
124.
Miyanoiri Y Takeda M Jee J Ono AM Okuma K Terauchi T Kainosho M 《Journal of biomolecular NMR》2011,51(4):425-435
Tryptophan (Trp) residues are frequently found in the hydrophobic cores of proteins, and therefore, their side-chain conformations,
especially the precise locations of the bulky indole rings, are critical for determining structures by NMR. However, when
analyzing [U–13C,15N]-proteins, the observation and assignment of the ring signals are often hampered by excessive overlaps and tight spin couplings.
These difficulties have been greatly alleviated by using stereo-array isotope labeled (SAIL) proteins, which are composed
of isotope-labeled amino acids optimized for unambiguous side-chain NMR assignment, exclusively through the 13C–13C and 13C–1H spin coupling networks (Kainosho et al. in Nature 440:52–57, 2006). In this paper, we propose an alternative type of SAIL-Trp with the [ζ2,ζ3-2H2; δ1,ε3,η2-13C3; ε1-15N]-indole ring ([12Cγ, 12Cε2] SAIL-Trp), which provides a more robust way to correlate the 1Hβ, 1Hα, and 1HN to the 1Hδ1 and 1Hε3 through the intra-residue NOEs. The assignment of the 1Hδ1/13Cδ1 and 1Hε3/13Cε3 signals can thus be transferred to the 1Hε1/15Nε1 and 1Hη2/13Cη2 signals, as with the previous type of SAIL-Trp, which has an extra 13C at the Cγ of the ring. By taking advantage of the stereospecific deuteration of one of the prochiral β-methylene protons, which was
1Hβ2 in this experiment, one can determine the side-chain conformation of the Trp residue including the χ2 angle, which is especially important for Trp residues, as they can adopt three preferred conformations. We demonstrated the
usefulness of [12Cγ,12Cε2] SAIL-Trp for the 12 kDa DNA binding domain of mouse c-Myb protein (Myb-R2R3), which contains six Trp residues. 相似文献
125.
Fukui K Ito S Ueno K Yamaguchi S Kyozuka J Asami T 《Bioorganic & medicinal chemistry letters》2011,21(16):4905-4908
Strigolactones (SLs) are rhizosphere communication chemicals. Recent studies of highly branched mutants revealed that SL or its metabolites work as a phytohormone to inhibit shoot branching. When SLs are exogenously applied to the rice d10-1 mutant that has a highly branched phenotype caused by a defect in the SL biosynthesis gene (CCD8), they inhibit tiller bud outgrowth (branching in rice) of the mutant. We focused our attention on the SL function as a phytohormone and tried to find new chemicals mimicking the hormonal action of SL by screening chemicals that inhibit branching of rice d10-1 mutant. Fortunately, we found 5-(4-chlorophenoxy)-3-methylfuran-2(5H)-one (3a) as a new chemical possessing SL-like activity against the rice d10-1 mutant. Then, we prepared several derivatives of 3a (3b-3k) to examine their ability to inhibit shoot branching of rice d10-1. These derivatives were synthesized by a one-pot coupling reaction between phenols and halo butenolide to give 5-phenoxy 3-methylfuran-2(5H)-one (3) derivatives, which possess a common substructure with SLs. Some of the derivatives showed SL-like activity more potently than GR24, a typical SL derivative, in a rice assay. As SLs also show activity by inducing seed germination of root parasitic plants, the induction activity of these derivatives was also evaluated. Here we report the structure-activity relationships of these compounds. 相似文献
126.
We examined CH/π hydrogen bonds using an ab initio fragment molecular orbital (FMO) method, combined with the CHPI program, to evaluate complexes of active (bound with agonist 1) and inactive (bound with inverse agonist 2) β2 adrenergic receptor (β(2)AR) states. In both states, we found that CH/π hydrogen bonds were present. Subtle changes in the binding pocket between the active and inactive states of β(2)AR were observed. Comparison of the CH/π networks in both states suggests that the networks differ at the β(2)AR core. Recombination of the CH/π hydrogen bonds occurred during conversion between the two states. We suggest that CH/π hydrogen bonds play a key role in ligand recognition and conversion between the active and inactive states. 相似文献
127.
Kazuhisa Kato Shinichi Maruyama Tadayoshi Hirai Kyoko Hiwasa-Tanase Tsuyoshi Mizoguchi Eiji Goto Hiroshi Ezura 《Plant signaling & behavior》2011,6(8):1172-1179
One of the ultimate goals of plant science is to test a hypothesis obtained by basic science and to apply it to agriculture and industry. A plant factory is one of the ideal systems for this trial. Environmental factors affect both plant yield and the accumulation of recombinant proteins for industrial applications within transgenic plants. However, there have been few reports studying plant productivity for recombinant protein in closed cultivation systems called plant factories.To investigate the effects of photosynthetic photon flux (PPF) on tomato fruit yield and the accumulation of recombinant miraculin, a taste-modifying glycoprotein, in transgenic tomato fruits, plants were cultivated at various PPFs from 100 to 400 (µmol m−2 s−1) in a plant factory. Miraculin production per unit of energy used was highest at PPF100, although miraculin production per unit area was highest at PPF300. The commercial productivity of recombinant miraculin in transgenic tomato fruits largely depended on light conditions in the plant factory. Our trial will be useful to consider the trade-offs between the profits from production of high-value materials in plants and the costs of electricity.Key words: light, molecular farming, recombinant miraculin, taste-modifying protein, transgenic tomato 相似文献
128.
Rapid recognition and signal transduction of mechanical wounding through various signaling molecules, including calcium (Ca2+), protein phosphorylation, and reactive oxygen species (ROS), are necessary early events leading to stress resistance in plants. Here we report that an Arabidopsis mitogen-activated protein kinase 8 (MPK8) connects protein phosphorylation, Ca2+, and ROS in the wound-signaling pathway. MPK8 is activated through mechanical wounding, and this activation requires direct binding of calmodulins (CaMs) in a Ca2+-dependent manner. MPK8 is also phosphorylated and activated by a MAPKK MKK3 in the prototypic kinase cascade, and full activation of MPK8 needs both CaMs and MKK3 in planta. The MPK8 pathway negatively regulates ROS accumulation through controlling expression of the Rboh D gene. These findings suggest that two major activation modes in eukaryotes, Ca2+/CaMs and the MAP kinase phosphorylation cascade, converge at MPK8 to monitor or maintain an essential part of ROS homeostasis. 相似文献
129.
Takeuchi H Mizoguchi H Doi Y Jin S Noda M Liang J Li H Zhou Y Mori R Yasuoka S Li E Parajuli B Kawanokuchi J Sonobe Y Sato J Yamanaka K Sobue G Mizuno T Suzumura A 《PloS one》2011,6(6):e21108
Background
Glutamate released by activated microglia induces excitotoxic neuronal death, which likely contributes to non-cell autonomous neuronal death in neurodegenerative diseases, including amyotrophic lateral sclerosis and Alzheimer''s disease. Although both blockade of glutamate receptors and inhibition of microglial activation are the therapeutic candidates for these neurodegenerative diseases, glutamate receptor blockers also perturbed physiological and essential glutamate signals, and inhibitors of microglial activation suppressed both neurotoxic/neuroprotective roles of microglia and hardly affected disease progression. We previously demonstrated that activated microglia release a large amount of glutamate specifically through gap junction hemichannel. Hence, blockade of gap junction hemichannel may be potentially beneficial in treatment of neurodegenerative diseases.Methods and Findings
In this study, we generated a novel blood-brain barrier permeable gap junction hemichannel blocker based on glycyrrhetinic acid. We found that pharmacologic blockade of gap junction hemichannel inhibited excessive glutamate release from activated microglia in vitro and in vivo without producing notable toxicity. Blocking gap junction hemichannel significantly suppressed neuronal loss of the spinal cord and extended survival in transgenic mice carrying human superoxide dismutase 1 with G93A or G37R mutation as an amyotrophic lateral sclerosis mouse model. Moreover, blockade of gap junction hemichannel also significantly improved memory impairments without altering amyloid β deposition in double transgenic mice expressing human amyloid precursor protein with K595N and M596L mutations and presenilin 1 with A264E mutation as an Alzheimer''s disease mouse model.Conclusions
Our results suggest that gap junction hemichannel blockers may represent a new therapeutic strategy to target neurotoxic microglia specifically and prevent microglia-mediated neuronal death in various neurodegenerative diseases. 相似文献130.