Studies on Regioselective Binding Mode of Steroid Molecules in Homology Modeled Cytochrome P450-2C11

In this study, we investigated the regioselective binding mode of steroid molecules and structure requirements for steroid molecules for 16[alpha]-hydroxylation by Cytochrome P450-2C11. Docking study by using the homology Cytochrome P450-2C11 indicated that 16[alpha]-hydroxylation is favored with steroidal molecules possessing the following components, 1) a bent A-B ring configuration (5[beta]-reduced), 2) C-3[alpha]-hydroxyl group, 3) C-17[beta]-acetyl group, and 4) methyl group at both the C-18 and C-19. These respective steroid components requirements such as A-B ring configuration and functional groups at C-3 and C-17 were defined as the inhibitory contribution factor. Overall results by rat CYP2C11 revealed that steroidal structure requirements resulted in causing an effective inhibition of [^3^H]progesterone 16[alpha]-hydroxylation by the adult male rat liver microsome. As far as docking of homology modeled CYP2C11 against investigated steroids is concerned, they are docked at the active site superimposed with flurbiprofen. It was also found that the distance between heme iron and C16[alpha]-H was between 4 to 6 Å and that the related angle was in the range of 180±45°

The Chemistry on Diterpenoids in 1970

This is one of a series of the annual reviews'-6) on diterpenoids chemistry by the author. In principle, in each section the full papers are first described and the short communications followed. The order of the journals follows the alphabet o

ON THE STRUCTURE AND STRUCTURAL UNITS OF AMORPHOUS METALS

application/pdfContrary to so far prevailing ideas to search for the structural disordering and defects in amorphous materials, the origin and varieties of ordering and ordered structures in amorphous metals and alloys were theoretically investigated. Bernal's polyhedrons, which partially included disordered and yet ordered structures, crystalline polyhedrons or clusters, and chemical compound clusters were three main subjects to be considered, and the importance of the last two varieties was mentioned in order to explain various experimental facts.紀要類(bulletin)departmental bulletin pape

MOSSBAUER SPECTROSCOPY OF AMORPHOUS ALLOYS

Electronic and atomic structures of ferromagnetic amorphous alloys containing iron as a major component are studied by means of Mossbauer spectroscopy. In accordance with many experimental results, which indicate that short range ordering in the atomic arrangements are considerably developed in the amorphous structure, the Mossbauer spectra of the amorphous alloys can be analyzed with the assumption that the near neighbour configurations are almost the same as those in the crystalline state. Comparing with the ordinary crystalline alloy structures, no essential difference or strangeness in the internal field distribution, isomer shift, quadrupole effect, and defect structures are found, differing from the generally accepted concept of simple random dense packing structure

Dislocation Theory of the Fatigue Fracture of Ductile Metals

A dislocation model of the fatigue fracture of ductile metals was proposed. Two parallel unlike rows of edge dislocations in the slip planes 10A or less distant from each other can have a chance to meet in a slip band during the cyclic stressing and to produce a long void with a rectangular cross-section by the annihilation of the leading dislocations, which will, then, grow into a long flat void sufficient to generate a fatigue crack by absorbing dislocations successively. It was shown that this dislocation model was fit for interpreting available experimental facts on the fatigue fracture of ductile metals

On the Formation of Dislocation Networks in Some Crystal Lattices

As in the preceding paper, based upon the assumption that dislocations initially formed in a solidified crystal lattice are small rings of a definite type such as proposed by Seitz, the subsequent growth and mutual connection of the dislocation rings and the eventual formation of networks were geometrically discussed in reference to some typical crystal lattices. The results would be available for surmising probable features of the dislocation networks

Role of proline residue in the channel-forming and catecholamine-releasing activities of the peptaibol, trichosporin-B-VIa

AbstractTrichosporin-B-VIa (TS-B-VIa) has a Pro14-kinked helical structure which is considered to be important for the formation of peptaibol-type ion-channels in lipid bilayer membranes. TS-B-VIa and its analog [Aid14]TS-B-VIa with Pro → Aib substitution at position 14, resulting in a straight helical structure, were tested for ion-channel-forming activity in planar lipid bilayer membranes and for ability to induce catecholamine secretion from cultured bovine adrenal chromaffin cells. Voltage-dependent multi-channel conductance, which is characteristic of TS-B-VIa, was also observed for [Aid14]TS-B-VIa. In single-channel measurements, current fluctuations induced by [Aid14]TS-B-VIa had a shorter life-time and showed fewer substates than those induced by TS-B-VIa. Catecholamine secretion induced by these peptides at low concentrations is completely Ca2+-dependent. At high concentrations, TS-B-VIa-induced secretion was partly independent of external Ca 2+, but this was not the case for the analog. The differences of behavior can be explained in terms of the differences of hydrophobicity, amphiphilicity, and magnitude of dipole moment due to the conformational changes around position 14 and the C-terminal domain caused by the Pro → Aib substitution