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In order to investigate the binding mode of E64-c (a synthetic cysteine proteinase inhibitor) to papain at the atomic level, the crystal structure of the complex was analysed by X-ray diffraction at 1.9 A (1 A is expressed in SI units as 0.1 nm) resolution. The crystal has a space group P2(1)2(1)2(1) with a = 43.37, b = 102.34 and c = 49.95 A. A total of… (More)
A coumarin-spiropyran conjugate (2) shows a CN(-)-selective fluorescence enhancement under UV irradiation. This enables accurate determination of very low levels of CN(-) (>0.5 μM).
To promote our better understanding of the dynamic stability of the bovine cathepsin B structure, which is characterized by an extra disulfide bond at Cys148-Cys252 from the other species, and of the binding stability of CA074 (a cathepsin B-specific inhibitor), molecular dynamics (MD) simulations were performed for the enzyme and its CA074 complex,… (More)
A rhodamine-cyclen conjugate (1) behaves as a highly sensitive and selective fluorescent chemosensor for Hg(2+). The high emission selectivity is due to the formation of 1-Hg(2+) 1:2 complex leading to spirocycle opening of 1.
A coumarin-amide-dipicolylamine linkage (L) was synthesized and used as a fluorescent receptor for metal cations in water. The receptor dissolved in water with neutral pH shows almost no fluorescence due to the photoinduced electron transfer (PET) from the amide and amine nitrogens to the excited state coumarin moiety. Coordination of Zn(2+) or Cd(2+) with… (More)
A simple copolymer consisting of N-isopropylacrylamide and coumarin-conjugated spiropyran (CS) units, poly(NIPAM-co-CS), has been synthesized. This polymer enables selective fluorometric detection of cyanide anion (CN(-)) in water at room temperature. The polymer itself shows almost no fluorescence, but shows a strong blue fluorescence in the presence of… (More)
The crystal structure of n-dodecylphosphorylcholine (n-C12PC)-bovine pancreas phospholipase A2 (PLA2) complex provided the following structural characteristics: (1) the dodecyl chain of n-C12PC was located at the PLA2 N-terminal helical region by hydrophobic interactions, which corresponds to the binding pocket of 2-acyl fatty acid chain (beta-chain) of the… (More)
To design a potent inhibitor specific for cathepsin B (rat liver), the tertiary structure was predicted based on the crystal structure of the papain complexed with (+)-(2S,3S)-3-(1-[N-(3-methylbutyl)amino]leucylcarbonyl)oxirane-2- carbolylic acid (E-64-c), a thiol protease inhibitor. Taking advantage of the structural characteristics of the predicted active… (More)
X-ray crystal structures of bovine pancreas prophospholipase A2 (proPLA2) inhibited by two amide-type inhibitors, [(R)-2-dodecanoyl-amino-1-hexanolphosphocholine (DAHPc) and (R)-2-dodecanoylamino-1-hexanolphosphoglycol (DAHPg)], were determined to R = 0.208 and 0.215 using reflections with up to 2.1 A resolution, respectively. Both complex crystals lacked… (More)
In order to investigate the stereo specificity of papain Sn subsites (n = 1-4) at the atomic level, two kinds of covalent-type inhibitors were designed based on the previous results on papain-E-64 and papain-E-64-c interactions, and their complex crystals with papain were analyzed by X-ray diffraction. The results show that the hydrophobic regions… (More)