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The structure of [Sc.sub.3][C.sub.82] metallofullerene was redetermined by employing the third generation synchrotron radiation powder data collected at SPring-8, where the [C.sub.2] encapsulated structure available to discuss the Sc-Sc interatomic distances were determined. The obtained structure shows the [C.sub.2] encapsulation in the [C.sub.80] cage together with the Sc-Sc interatomic distances.

The prolyl aminopeptidase complexes of Ala-TBODA [2-alanyl-5-tert-butyl-(1, 3, 4)-oxadiazole] and Sar-TBODA [2-sarcosyl-5-tert-butyl-(l, 3, 4)-oxadiazole] were analyzed by X-ray crystallography at 2.4 resolution. Frames of alanine and sarcosine residues were well superimposed on each other in the pyrrolidine ring of proline residue, suggesting that Ala and Sar are recognized as parts of this ring of proline residue by the presence of a hydrophobic proline pocket at the active site. Interestingly, there was an unusual extra space at the bottom of the hydrophobic pocket where proline residue is fixed in the prolyl aminopeptidase. Moreover, 4-acetyloxyproline-[beta]NA (4-acetyloxyproline [beta]-naphthylamide) was a better substrate than Pro-[beta]NA. Computer docking simulation well supports the idea that the 4-acetyloxyl group of the substrate fitted into that space. Alanine scanning mutagenesis of Phe139, Tyr149, Tyrl50, Phe236, and Cys271, consisting of the hydrophobic pocket, revealed that all of these five residues are involved significantly in the formation of the hydrophobic proline pocket for the substrate. Tyr149 and Cys271 may be important for the extra space and may orient the acetyl derivative of hydroxyproline to a preferable position for hydrolysis. These findings imply that the efficient degradation of collagen fragment may be achieved through an acetylation process by the bacteria.

Author(s): Maiko Isshiki (corresponding author) [1, 2]; Tetsuo Irifune (corresponding author) [1]; Kei Hirose [3]; Shigeaki Ono [4]; Yasuo Ohishi [2]; Tetsu Watanuki [5]; Eiji Nishibori [6]; Masaki Takata [2, [...]

Yttrium atom enclosed in the cage of fullerenes with various metal atoms is located away from the centre of the C(sub 82) molecule with strong binding to the carbon cage in endohedral metallofullerenes as revealed by a synchrotron X-ray power diffraction study of the metallofullerenes. These observations are first over their kind to provide a concrete proof for the endohedral nature of the metallofullerenes.

1-Ferrocenylethynylanthraquinone, which is a donor (D)-acceptor conjugated compound consisting of a ferrocene (Fc) acting as a donor, an anthraquinone (Aq) acting as an acceptor, and an ethynyl linker, has undergone a cyclocondensation reaction with strong organic acid and has formed 2-ferrocenyloxodihydrodibenzochromenylium salts are characterized as conjugated donor-acceptor compounds. The studies have shown that the electrostatic interaction between the 2-ferrocenyloxodihydrodibenzochromenylium moiety and the counteranion might affect the occurrence of variable-temperature (VT).

The crystal structure of the single-component molecular metal [Au[(tmdt).sub.2]] is examined at pressures up to 10.7 GPa in order to examine whether the high-pressure structure reflects the crystal's metallic nature. The crystal lattice of [Au[(tmdt).sub.2]] is stabilized by increasing the intermolecular overlapping of the conduction molecular orbitals having large amplitudes on peripheral S atoms.

The syntheses, crystal structures and physical properties of novel cobalt complexes with tetrathiavulvalene-type (TTF-type) dithiolate ligands are described. Complex [[Co[(TTF-dithiolate).sub.2]].sub.2] is a novel single-component molecular conductor with a dimeric molecular structure and metallic properties down to very low temperatures.

The configuration of La ions of La2@C80 in the fullerene cage was investigated by use of quantum chemical calculations. The experimental and theoretical investigation of the Raman spectrum revealed that the symmetry of molecular vibration is dramatically reduced and resulting vibrational modes were successfully assigned.

A detailed information is presented on the antiferromagnetic transition of (Au(tmdt)2) around 110K (T(sub N) and its spin-flop behavior and the electromagnetic properties of the 'molecular alloys' of (Ni(tmdt)2) and (Au(tmdt)2). The temperature dependence of the resistivities of the compressed pellet samples of the novel alloys of single-component molecular metals, (Ni(sub 1-x)Au(sub x)(tmdt)2), showed the system to be essentially metallic down to low temperature.

The crystal structure of [Au(tmdt)(sub 2)](super 0+) was determined by using synchrotron radiation powder X-ray diffraction data. Resistivity and susceptivility measurements on the specimen powder sample showed that it undergoes a magnetic transition around 100 K without loss of its high conductivity.