The crystal structure of the complex formed by bovine trypsin and Bowman-Birk type protease inhibitor AB-I extracted from azuki beans (Vigna angularis) 'Takara' has been analyzed. The structure was solved by the application of the phase combination of single isomorphous phases and trypsin model phases, followed by phase improvement using the iterative Fourier technique. From the resulting electron density map, a three-dimensional atomic model of the trypsin binding domain of AB-I has been built. The peptide chain at the trypsin reactive site turns back sharply at Pro29 and forms a 9-residue ring (Cys24-Cys32). The 'front side' of this ring, consisting of the reactive site (Cys24-Met28), interacts with trypsin in a similar manner to other families of inhibitors and forms a stable complex, which seems to be maintained by the interactions with the 'back side' of this ring (Pro29-Cys34). The similar spatial arrangements of the 'back side' of this inhibitor and the 'secondary contact region' of the other inhibitors with respect to the reactive site suggest an important common role of these regions in exhibiting inhibitory activity.

Novel molybdenum-and tungsten-based catalysts induced stereospecific ring-opening metathesis polymerization (ROMP) of cycloolefins to produce a new class of crystalline polymers. Various monomeric molybdenum(VI) and tungsten(VI) complexes of the general formula M()O)(O-Ar) 4 (M ) Mo or W;(O-Ar)4 is two biphenolate or four phenolate ligands) were prepared. These catalysts exhibited moderate ROMP activity in the presence of cocatalyst such as n-BuLi and Et3Al. The molybdenum and tungsten complexes bearing substituted biphenolate ligands such as oxomolybdenum(VI) bis(racemic-5,5′,6,6′-tertamethyl-3,3′-di-tert-butyl-1,1′-biphenyl-2,2′-diolate) promoted cis and isospecific ROMP of endodicyclopentadiene (cis > 90% and meso > 95%). The novel ternary and quarternary catalysts such as MoOCl 4-biphenolate-n-BuLi (1:2:2) were developed as a new useful methodology to control the stereoselectivity of the ROMP. Hydrogenation of the cis-isotactic poly(endo-dicyclopentadiene)s and poly-(norbornene)s provided novel crystalline polymers with high melting points (295 °C, ∆H ) 50 J/g; 175 °C, ∆H ) 60 J/g, respectively), which can be regarded as a new class of crystalline polymers.

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Crystalline styrene-butadiene-styrene (SBS) triblock copolymers consisting of elastic cispolybutadiene (cis-PB) chemically bonded with crystallizable syndiotactic polystyrene (syn-PS) were synthesized through a stereospecific sequential triblock copolymerization of S with B catalyzed by C 5 Me 5 TiMe 3 /B(C 6 F 5 ) 3 / trioctylaluminum (Al(oct) 3 ) under controllable polymerization conditions. The first polymerization step was conducted at -25 °C, yielding syn-PS with controllable molecular weight by changing the polymerization time.The second one was started with the addition of excess B to the progressing syn-PS polymerization at -40 °C, yielding syn-PS/cis-PB diblock copolymer with high block efficiencies. The third one was conducted at -25 °C just by removal of the unreacted B in order to enhance the reinsertion and propagation of the remained S, yielding crystalline SBS triblock copolymers with relatively high PS compositions. The livingness of the whole polymerization process was confirmed through a linear increase of the molecular weights of the polymer products obtained in each step against their polymer yields, while keeping the polydispersity values almost constant. The 13 C NMR analysis of the copolymer product proves that the PS blocks were highly syndiotactic ([rrrr] > 95%), and the PB block was primarily cis-1,4 structure (>70%). Cross-fractionation chromatography (CFC) was used to evaluate the contamination of the dead polymers in the crystalline SBS. Transmission electronic microscopy (TEM) was used to observe the phased separation morphology of the PS and PB blocks in the crystalline SBS. The existence of the syn-PS blocks in the crystalline SBS was further confirmed with the observation of a strong endothermic peak at 272 °C in their differential scanning calorimetry (DSC) curves. Preliminary results on the heat deformation stability as well as the chemical resistance property of this new material have also been evaluated in comparison with those of the corresponding anionic SBS materials.