Takafumi Ueno 교수

Deep penetration by substrates through the size-restricted channels of an apo-ferritin cage results in size-selective olefin hydrogenation at the Pd nanocluster core (see picture). The encapsulated zero-valent cluster is synthesized in situ by chemical reduction of PdII ions in the apo-ferritin cage.

New methods for the synthesis of artificial metalloenzymes are important for the construction of novel biocatalysts and biomaterials. Recently, we reported new methodology for the synthesis of artificial metalloenzymes by reconstituting apo-myoglobin with metal complexes (Ohashi, M. et al., Angew Chem., Int. Ed. 2003, 42, 1005-1008). However, it has been difficult to improve their reactivity, since their crystal structures were not available. In this article, we report the crystal structures of

We have succeeded in preparing Au/Pd core-shell nanoparticles in apo-ferritin and improving the catalytic reactivity of olefin hydrogenation relative to Pd0 nanoparticles in the cage.

Apo-myoglobin (apo-Mb) and apo-A71GMb were successfully reconstituted with FeIII(salophen) (1) (salophen = N,N'-bis(salicylidene)-1,2-phenilenediamine), Fe(III)(3,3'-Me2-salophen) (2), and FeIII(5,5'-t-Bu2-salophen) (3). The crystal structure of 2.apo-A71GMb shows the tight binding of the complex in the Mb cavity, while in wild-type apo-Mb it is highly disordered due to the steric repulsion with Ala71. Furthermore, the structure of 2.apo-A71GMb suggests a possible accommodation of a small substr

Accumulation of metal ions on protein surfaces is an important subject in the field of materials science because these processes are applicable to the preparation of bioinspired inorganic materials. While previous studies related to this subject have focused on the preparation of nanomaterials using protein scaffolds, the detailed processes of metal ion deposition and metal core formation on a protein surface require clarification. Elucidation of the coordination structures of multinuclear metal

Protein cages can serve as bioinorganic molecular templates for functionalizing metal compounds to regulate cellular signaling. We succeeded in developing a photoactive CO-releasing system by constructing a composite of ferritin (Fr) containing manganese-carbonyl complexes. When Arg52 adjacent to Cys48 of Fr is replaced with Cys, the Fr mutant stabilizes the retention of 48 Mn-carbonyl moieties, which can release the CO ligands under light irradiation, although wild-type Fr retains very few Mn m

Metallcluster in einer Proteinkapsel: Solche in situ durch chemische Reduktion von Palladium(II)-Ionen im Apoferritin-Käfig erzeugte Cluster ermöglichen größenselektive Olefin-Hydrierungen wegen der durch die Ferritinkanäle bedingten Größenlimitierung (siehe Schema).

Carbon monoxide (CO) is recognized as one of the most important gas signaling molecules involved in governing various therapeutic responses. Intracellular generation of CO is spatiotemporally controlled by catalytic reactions of heme oxygenases (HOs). Thus, the ability to control intracellular CO delivery with modulation of the CO-release rate in specific amounts and locations is expected to improve our fundamental understanding of the functions of CO and the development of clinical applications

Spherical protein cages such as an iron storage protein, ferritin, have great potential as nanometer-scale capsules to assemble and store metal ions and complexes. We report herein the synthesis of a composite of an apo-ferritin cage and Ru(p-cymene) complexes. Ru complexes were efficiently incorporated into the ferritin cavity without degradation of its cage structure. X-Ray crystallography revealed that the Ru complexes were immobilized on the interior surface of the cage mainly by the coordin

An artificial photoinduced electron-transfer system has been constructed by accumulating redox cofactors in a myoglobin crystal. The crystal space allowed the construction of a site-specific dense array, and the different redox cofactors had low reorganization energies, as observed in native photosynthesis. A charge-separated state with a half-life 2800 times longer than that of one previously reported in organic solution was achieved. Detailed facts of importance to specialist readers are publi

Porous protein crystals, which are protein assemblies in the solid state, have been engineered to form catalytic vessels by the incorporation of organometallic complexes. Ruthenium complexes in cross-linked porous hen egg white lysozyme (HEWL) crystals catalyzed the enantioselective hydrogen-transfer reduction of acetophenone derivatives. The crystals accelerated the catalytic reaction and gave different enantiomers based on the crystal form (tetragonal or orthorhombic). This method represents a

Porous protein crystals have the potential to provide new porous materials due to their unique chemical environments composed of amino acid residues periodically exposed at the surface of the solvent channels in the crystal lattice. This enables accumulation of external compounds in special arrangements by metal coordination interactions or by chemical modifications. This article presents a review of advances in the recently established field of porous protein crystals.