プルトニウム・ウラン共晶析法による簡易再処理システムの開発

textapplication/pdfdepartmental bulletin pape

A balloon-borne very long baseline interferometry experiment in the stratosphere: Systems design and developments

application/pdfAdvances in Space Research. 2019, 63 (1), P.779-793journal articl

Observation of B̅0→DsJ*(2317)+K- Decay

journal articl

Solar neutrino measurements in Super-Kamiokande-II

The results of the second phase of the Super-Kamiokande solar neutrino measurement are presented and compared to the first phase. The solar neutrino flux spectrum and time variation as well as oscillation results are statistically consistent with the first phase and do not show spectral distortion. The timedependent flux measurement of the combined first and second phases coincides with the full period of solar cycle 23 and shows no correlation with solar activity. The measured 8B total flux is (2:38± 0.05(stat.)/begin+0.16 // -0.15/end (sys.)) × 10^6 cm^{-2} s^{-1} and the day-night difference is found to be (-6.3 ±4.2(stat.)±3.7(sys.))%.There is no evidence of systematic tendencies between the first and second phases.journal articl

Highly Selective DNA Modification by Ambient O₂-Activated Co(II)·Lys-Gly-His Metallopeptides

Highly Selective DNA Modification by Ambient O2-Activated Co(II)·Lys-Gly-His Metallopeptide

DNA Strand Scission by Dioxygen + Light-Activated Cobalt Metallopeptides

DNA Strand Scission by Dioxygen + Light-Activated Cobalt Metallopeptide

Combinatorial Optimization of the DNA Cleaving Ni(II)·Xaa-Xaa-His Metallotripeptide Domain^†

A positional-scanning combinatorial protocol was employed to optimize the deoxyribose-based cleavage of B-form DNA by Ni(II)·Xaa-Xaa-His metallopeptides. This procedure employed 18 naturally occurring amino acids (excluding Cys and Trp) to generate two libraries in which the first and second positions of the peptide ligand were varied. Increased direct DNA cleavage relative to Ni(II)·Gly-Gly-His was observed when (1) the amino-terminal peptide position contained Pro, Met, Arg, or Lys (with Pro exhibiting the greatest activity) and (2) the second peptide position contained Lys, Arg, Met, Ser, or Thr (with Lys exhibiting the greatest activity); the optimized metallopeptide, Ni(II)·Pro-Lys-His, was found to cleave DNA an order of magnitude better than Ni(II)·Gly-Gly-His. While metal complexation and the A/T-rich site selectivity of the optimized metallopeptides were not altered, DNA binding affinity was slightly increased relative to Ni(II)·Gly-Gly-His, however, not to an extent necessary to account for the observed increase in reactivity. Examination of molecular models of Ni(II)·Pro-Lys-His bound to the minor groove of DNA via hydrogen bonding of the His N3 imidazole hydrogen to the N3 of adenine or O2 of thymine suggests that the Pro residue can make hydrophobic contacts with the sugars lining the walls of the groove while the Lys residue is able to form a salt bridge with a proximal phosphate; with these interactions, the metal center is poised to abstract the C4‘-H of an adjacent nucleotide suggesting that noncovalent interactions result in a positioning which contributes to increased DNA cleavage activity

() Minor groove widths of DNA base-pair steps (from 3DNA calculations) in the absence (open circle) and presence (black diamond) of netropsin

<p><b>Copyright information:</b></p><p>Taken from "A host–guest approach for determining drug–DNA interactions: an example using netropsin"</p><p>Nucleic Acids Research 2005;33(13):4106-4116.</p><p>Published online 27 Jul 2005</p><p>PMCID:PMC1181240.</p><p>© The Author 2005. Published by Oxford University Press. All rights reserved</p> () Stereo diagram of structures of DNA in the absence (red) and presence (blue) of netropsin (r.m.s.d = 0.9 Å). Superimpositioning of C1′ of all 16 bp was done using O ()

Superimposed netropsin molecules from our structure and several known netropsin–DNA structures

<p><b>Copyright information:</b></p><p>Taken from "A host–guest approach for determining drug–DNA interactions: an example using netropsin"</p><p>Nucleic Acids Research 2005;33(13):4106-4116.</p><p>Published online 27 Jul 2005</p><p>PMCID:PMC1181240.</p><p>© The Author 2005. Published by Oxford University Press. All rights reserved</p> Structures of the atoms from the guanidinium end through the first pyrrole ring were superimposed using LSQKAB in CCP4i (,). Reported structures are labeled by their Protein Data Bank ID. This work in blue; 101D in red, r.m.s.d = 0.4 Å; 121D in orange, r.m.s.d. = 0.5 Å; 195D in green, r.m.s.d. = 0.2 Å; 261D in magenta, r.m.s.d = 0.3 Å

Ni(II)·Xaa-Xaa-His Induced DNA Cleavage: Deoxyribose Modification by a Common “Activated” Intermediate Derived from KHSO₅, MMPP, or H₂O₂

Ni(II) chelated peptides of the form NH2-Xaa-Xaa-His-CONH2 (Ni(II)·Xaa-Xaa-His) mediate deoxyribose damage through C4‘−H abstraction of a targeted nucleotide when activated with KHSO5 (oxone), MMPP (magnesium monoperoxyphthalate), or H2O2. The products released and identified in comparison to the authentic C4‘−H oxidant Fe(II)·bleomycin included fragmented DNA terminating in 5‘-phosphates, 3‘-phosphates, and 3‘-phosphoglycolates; upon treatment of Ni(II)·Xaa-Xaa-His cleavage reactions with NaOH or NH2NH2, fragmented DNA 3‘-termini were released consistent with the intermediate formation of keto-aldehyde abasic (alkaline-labile) sites. In addition, nucleobases and nucleobase propenals were detected in proportions consistent with abasic site and 3‘-phosphoglycolate termini formation, respectively. These results indicate that Ni(II)·Xaa-Xaa-His metallopeptides, like Fe(II)·bleomycin, degrade DNA through two pathways resulting from an initial C4‘−H modification. Importantly, the partitioning between these two pathways appears to be dependent on the structure of the Ni(II)·Xaa-Xaa-His metallopeptide employed in the cleavage reaction and the nucleotide sequence targeted. Further studies also indicate that metallopeptide activation with KHSO5, MMPP, or H2O2 yields identical reaction products and sequence-selective DNA cleavage suggesting the formation of a common “activated” metallopeptide responsible for C4‘−H deoxyribose damage, quite possibly a metal-bound hydroxyl radical. These studies also demonstrate that metallopeptide activation with KHSO5 is condition-dependent resulting in (1) C4‘−H damage in common with MMPP or H2O2 under relatively “low” ionic strength conditions (10 mM Na-cacodylate, pH 7.5, equimolar KHSO5/metallopeptide) or (2) guanine nucleobase oxidation under higher ionic strength conditions (100 mM NaCl, 10 mM phosphate, pH 7.0, excess KHSO5)