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131.
Takashima H Yoshida T Ishino T Hasuda K Ohkubo T Kobayashi Y 《The Journal of biological chemistry》2005,280(12):11340-11346
Holo-neocarzinostatin (holo-NCS) is a complex protein carrying the anti-tumor active enediyne ring chromophore by a scaffold consisting of an immunoglobulin-like seven-stranded anti-parallel beta-barrel. Because of the labile chromophore reflecting its extremely strong DNA cleavage activity and complete stabilization in the complex, holo-NCS has attracted much attention in clinical use as well as for drug delivery systems. Despite many structural analyses for holo-NCS, the chromophore-releasing mechanism to trigger prompt attacks on the target DNA is still unclear. We determined the three-dimensional structure of the protein and the internal motion by multinuclear NMR to investigate the releasing mechanism. The internal motion studied by 13C NMR methine relaxation experiments showed that the complex has a rigid structure for its loops as well as the beta-barrel in aqueous solution. This agrees with the refined NMR solution structure, which has good convergence in the loop regions. We also showed that the chromophore displayed a similar internal motion as the protein moiety. The structural comparison between the refined solution structure and x-ray crystal structure indicated characteristic differences. Based on the findings, we proposed the chromophore-releasing mechanism by a three-state equilibrium, which sufficiently describes both the strong binding and the prompt releasing of the chromophore. We demonstrated that we could bridge the dynamic properties and the static structure features with simple kinetic assumptions to solve the biochemical function. 相似文献
132.
133.
Ohe G Okamoto M Oshikawa T Furuichi S Nishikawa H Tano T Uyama K Bando T Yoshida H Sakai T Himeno K Sato M Ohkubo S 《Cancer immunology, immunotherapy : CII》2001,50(5):251-259
We have isolated a 55 kDa protein from the seed extract of Aeginetia indica L. (AIL), a parasitic plant, by affinity chromatography on an N-hydroxysuccinimide-activated Sepharose High Performance column
bound with F3, a monoclonal antibody that neutralizes the cytokine-inducing and anti-tumor effect of AIL. In the present study,
we examined this protein (AILb-A) for cytokine induction and anti-tumor effects by animal study, using syngeneic Meth-A tumor-bearing
BALB/c mice, in which the Th2 response is genetically dominant. AILb-A administration resulted in markedly increased levels
of Th1 cytokines [interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-2, IL-12 and IL-18] in the sera derived
from Meth-A-bearing mice. The in vitro re-stimulation with AILb-A of splenocytes derived from AILb-A-primed mice also selectively
induced Th1-type cytokines and antigen-specific killer cell activity. The neutralizing test using cytokine-specific antibodies
revealed that AILb-A-induced IL-18 plays a most significant role for IFN-γ- and killer cell-inducing activities. Furthermore,
IL-12 and IL-18 induced by AILb-A inhibited specifically IL-10 and IL-4 production, respectively. Finally, we examined the
anti-tumor effect of AILb-A in both Meth-A-bearing BALB/c mice and Meth-A-bearing nude mice with BALB/c background. AILb-A
exhibited a striking anti-tumor effect in normal BALB/c mice inoculated with Meth-A cells. In athymic nude mice, the anti-tumor
effect of AILb-A was relatively weak. These findings strongly suggested that AILb-A is a potent Th1 inducer and may be a useful
immunotherapeutic agent for patients with malignant diseases.
Received: 27 July 2000 / Accepted: 13 March 2001 相似文献
134.
Alzheimer's disease and estrogen 总被引:6,自引:0,他引:6
Honjo H Kikuchi N Hosoda T Kariya K Kinoshita Y Iwasa K Ohkubo T Tanaka K Tamura T Urabe M Kawata M 《The Journal of steroid biochemistry and molecular biology》2001,76(1-5):227-230
The preventive effect of estrogen on Alzheimer's disease (AD) has become clear with epidemiological data. Therapeutic effects of estrogen have not yet been established. In this presentation, we report our new basic and clinical data. The estrogen receptor, (ER), and ERβ mRNA were investigated in rat brain. Estradiol-17β (E2) treatment following OVX reduced the levels of ER mRNA in the hypothalamus. In the substantia innominata (SI), the number of choline acetyltransferase immunoreacive cells increased significantly in the estrogen treatment rat. The neurons in SI projecting to the forebrain cortex contained ER. Increasing amounts of intracellular calcium, peroxidation, and apoptosis with amyloid β were suppressed in neuronal cells from rat pheochromocytoma (PC12) cells with E2. ER cDNA transfected PC 12 cells elaborated more neurite-like processes with E2. In clinics, we are currently preparing vaginal progesterone tablets, which essentially may concentrate in the endometrium to prevent endometrial cancer, with few general circulation of progesterone inviting less depression. The therapeutic effects of cyclic estrogen, such as its preventive effect, are suggested in these studies, at least on mild AD. 相似文献
135.
Purification of a novel serine proteinase inhibitor from the skeletal muscle of white croaker (Argyrosomus argentatus) 总被引:1,自引:0,他引:1
Cao MJ Osatomi K Matsuda R Ohkubo M Hara K Ishihara T 《Biochemical and biophysical research communications》2000,272(2):485-489
A novel serine proteinase inhibitor has been purified to homogeneity from the skeletal muscle of white croaker (Argyrosomus argentatus). The purification was carried out by ammonium sulfate fractionation, DEAE-Sephacel, heating treatment followed by column chromatographies on SP-Sepharose, Sephadex G-150 and gel-filtration high performance liquid chromatography. The molecular mass of the inhibitor was 55 kDa as estimated by SDS-PAGE and gel filtration. It specifically inhibited a myofibril-bound serine proteinase (MBSP) isolated from the skeletal muscle of lizard fish (Saurida wanieso). No inhibition, however, was detected toward other serine proteinases such as bovine trypsin, bovine chymotrypsin and a myofibril-bound serine proteinase from carp (Cyprinus carpio) muscle. Interestingly, the sequences of tryptic digested peptide fragments of MBSPI revealed high identity to that of porcine phosphoglucose isomerase (PGI) (76%) and other PGIs. Furthermore, purified MBSPI exhibits PGI activity, suggesting the inhibitor is a protein closely related to PGI. When rabbit muscle PGI was investigated, it also specifically suppressed the activity of MBSP. It thus strongly suggests that MBSPI is actually PGI and conversely, PGI is a specific inhibitor toward myofibril-bound serine proteinase(s). 相似文献
136.
R Kageyama H Ohkubo S Nakanishi 《Biochemical and biophysical research communications》1985,129(3):826-832
Inflammatory responses of the angiotensinogen mRNA in rat liver and brain were examined by RNA blot-hybridization analysis with use of a cDNA probe specific for rat angiotensinogen. The angiotensinogen mRNA in the liver increased rapidly during the first 5 h following the administration of Escherichia coli lipopolysaccharide, and at maximum level of induction, the mRNA increased approximately 5-fold over its normal level. The levels of the mRNA increased with increasing doses of lipopolysaccharide, the half-maximal dose being approximately 1 microgram/100 g body weight. In contrast, no such increase was observed in the brain angiotensinogen mRNA. Thus, the expression of the rat angiotensinogen mRNA is regulated in a tissue-specific manner in response to induction of acute inflammation. 相似文献
137.
Atsushi Tabata Kazuto Ohkura Yukimasa Ohkubo Toshifumi Tomoyasu Hisashi Ohkuni Robert A. Whiley Hideaki Nagamune 《Microbiology and immunology》2014,58(3):155-171
Cholesterol‐dependent cytolysins (CDCs) are bacterial pore‐forming toxins secreted mainly by pathogenic Gram‐positive bacteria. CDCs generally recognize and bind to membrane cholesterol to create pores and lyse target cells. However, in contrast to typical CDCs such as streptolysin O, several atypical CDCs have been reported. The first of these was intermedilysin, which is secreted by Streptococcus intermedius and has human cell‐specificity, human CD59 (huCD59) being its receptor. In the study reported here, the diversity of receptor recognition among CDCs was investigated and multi‐receptor recognition characteristics were identified within this toxin family. Streptococcus mitis‐derived human platelet aggregation factor (Sm‐hPAF) secreted by S. mitis strain Nm‐65 isolated from a patient with Kawasaki disease was previously shown to hemolyze erythrocytes in a species‐dependent manner, its maximum activity being in human cells. In the present study, it was found that Sm‐hPAF recognizes both membrane cholesterol and huCD59 as receptors for triggering pore‐formation. Moreover, vaginolysin (VLY) of Gardnerella vaginalis showed similar characteristics to Sm‐hPAF regarding receptor recognition. On the basis of the results presented here, the mode of receptor recognition of CDCs can be categorized into the following three groups: (i) Group I, comprising typical CDCs with high affinity to cholesterol and no or very little affinity to huCD59; (ii) Group II, including atypical CDCs such as ILY, with no or very little affinity to cholesterol and high affinity to huCD59; and (iii) Group III, which contains atypical CDCs such as Sm‐hPAF and VLY with affinity to both cholesterol and huCD59. 相似文献
138.
Kei Asayama Lutgarde Thijs Jana Brguljan-Hitij Teemu J. Niiranen Atsushi Hozawa José Boggia Lucas S. Aparicio Azusa Hara Jouni K. Johansson Takayoshi Ohkubo Christophe Tzourio George S. Stergiou Edgardo Sandoya Ichiro Tsuji Antti M. Jula Yutaka Imai Jan A. Staessen for the International Database of Home Blood Pressure in Relation to Cardiovascular Outcome investigators 《PLoS medicine》2014,11(1)
Background
The Global Burden of Diseases Study 2010 reported that hypertension is worldwide the leading risk factor for cardiovascular disease, causing 9.4 million deaths annually. We examined to what extent self-measurement of home blood pressure (HBP) refines risk stratification across increasing categories of conventional blood pressure (CBP).Methods and Findings
This meta-analysis included 5,008 individuals randomly recruited from five populations (56.6% women; mean age, 57.1 y). All were not treated with antihypertensive drugs. In multivariable analyses, hazard ratios (HRs) associated with 10-mm Hg increases in systolic HBP were computed across CBP categories, using the following systolic/diastolic CBP thresholds (in mm Hg): optimal, <120/<80; normal, 120–129/80–84; high-normal, 130–139/85–89; mild hypertension, 140–159/90–99; and severe hypertension, ≥160/≥100.Over 8.3 y, 522 participants died, and 414, 225, and 194 had cardiovascular, cardiac, and cerebrovascular events, respectively. In participants with optimal or normal CBP, HRs for a composite cardiovascular end point associated with a 10-mm Hg higher systolic HBP were 1.28 (1.01–1.62) and 1.22 (1.00–1.49), respectively. At high-normal CBP and in mild hypertension, the HRs were 1.24 (1.03–1.49) and 1.20 (1.06–1.37), respectively, for all cardiovascular events and 1.33 (1.07–1.65) and 1.30 (1.09–1.56), respectively, for stroke. In severe hypertension, the HRs were not significant (p≥0.20). Among people with optimal, normal, and high-normal CBP, 67 (5.0%), 187 (18.4%), and 315 (30.3%), respectively, had masked hypertension (HBP≥130 mm Hg systolic or ≥85 mm Hg diastolic). Compared to true optimal CBP, masked hypertension was associated with a 2.3-fold (1.5–3.5) higher cardiovascular risk. A limitation was few data from low- and middle-income countries.Conclusions
HBP substantially refines risk stratification at CBP levels assumed to carry no or only mildly increased risk, in particular in the presence of masked hypertension. Randomized trials could help determine the best use of CBP vs. HBP in guiding BP management. Our study identified a novel indication for HBP, which, in view of its low cost and the increased availability of electronic communication, might be globally applicable, even in remote areas or in low-resource settings. Please see later in the article for the Editors'' Summary 相似文献139.
Ken Yamada Akihiro Ohkubo Yousuke Esaka Takashi Kanamori Yoshiaki Masaki Kohji Seio Mitsuo Sekine 《Bioorganic & medicinal chemistry letters》2013,23(11):3448-3451
To increase base recognition capability and sensitivity, we propose the separation of a commonly used single-probe system for oligonucleotide analysis into a set of three probes: a fluorophore-labeled probe, a promoter probe, and a short probe. In this study, we found that the probes of only 4 nt in length can selectively bind the corresponding gap site on complexes consisting of the target, fluorophore-labeled probe, and promoter probe, exhibiting a more than 14-fold difference in ligation between the matched and mismatched sequences. Moreover, we demonstrated that the immobilized short probes accurately recognized the sequences of the gap sites. 相似文献
140.
Kenji Yamada Yusaku Hattori Takeshi Inde Takashi Kanamori Akihiro Ohkubo Kohji Seio Mitsuo Sekine 《Bioorganic & medicinal chemistry letters》2013,23(3):776-778
The consecutive arrangement of 2′-deoxy-6-thioguanosines (s6Gs) and 4-thiothymidines (s4Ts) in antiparallel triplex-forming oligonucleotides (TFOs) considerably stabilized the resulting antiparallel triplexes with high base recognition ability by the strong stacking effects of thiocarbonyl groups. This result was remarkable because chemical modifications of the sugar moieties and nucleobases of antiparallel TFOs generally destabilize triplex structures. Moreover, in comparison with unmodified TFOs, it was found that TFOs containing s6Gs and s4Ts could selectively bind to the complementary DNA duplex but not to mismatched DNA duplexes or single-stranded RNA. 相似文献