Haruki Yamamoto

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Proteins binding to amyloid beta-protein (Abeta) may modulate the accumulation of Abeta in Alzheimer's disease (AD) brain. We developed a monomeric Abeta column for isolation of the proteins binding to Abeta from rat brain. By amino acid sequence analysis and immunoreactivity with specific antibodies, we identified three new Abeta-binding proteins,(More)
Heliobacteria have the simplest photosynthetic apparatus, i.e., a type-I reaction center lacking a peripheral light-harvesting complex. Bacteriochlorophyll (BChl) g molecules are bound to the reaction center complex and work both as special-pair and antenna pigments. The C8-ethylidene group formation for BChl g is the last missing link in biosynthetic(More)
The form and differentiation of the endoplasmic reticulum has been studied in the developing sperm of the crayfish, Cambaroides japonicus. Throughout development a relationship between the nuclear envelope and cytoplasmic portion of the endoplasmic reticulum has been shown to exist. Furthermore, large contributions of material from the nuclear envelope to(More)
Dark-operative protochlorophyllide (Pchlide) oxido-reductase (DPOR) is a nitrogenase-like enzyme that catalyzes Pchlide reduction, the penultimate step of chlorophyll a biosynthesis. DPOR is distributed widely among oxygenic phototrophs such as cyanobacteria, green algae and gymnosperms. To determine how DPOR operates in oxygenic photosynthetic cells, we(More)
Chlorophyllous pigments are essential for photosynthesis. Bacteriochlorophyll (BChl) b has the characteristic C8-ethylidene group and therefore is the sole naturally occurring pigment having an absorption maximum at near-infrared light wavelength. Here we report that chlorophyllide a oxidoreductase (COR), a nitrogenase-like enzyme, showed distinct substrate(More)
Dark-operative protochlorophyllide (Pchlide) oxidoreductase (DPOR) is a nitrogenase-like enzyme consisting of the two components, L-protein (a ChlL dimer) and NB-protein (a ChlN-ChlB heterotetramer), to catalyze Pchlide reduction in Chl biosynthesis. While nitrogenase is distributed only among certain prokaryotes, the probable structural genes for DPOR are(More)
Although cyanobacteria are photoautotrophs, they have the capability for heterotrophic metabolism that enables them to survive in their natural habitat. However, cyanobacterial species that grow heterotrophically in the dark are rare. It remains largely unknown how cyanobacteria regulate heterotrophic activity. The cyanobacterium Leptolyngbya boryana grows(More)
In the present electron microscopic study of spermatogenesis in the crayfish, Cambaroides japonicus, it was possible to clarify several aspects of the unusual differentiation which leads to the production of an aflagellate sperm. The centriole is followed from the metaphase of the second spermatocyte division to the time at which, in the nearly mature(More)
In previous studies we have demonstrated that chlorophyllide a oxidoreductases (CORs) from bacteriochlorophyll (BChl) a-producing Rhodobacter species and BChl b-producing Blastochloris viridis show distinct substrate recognition and different catalytic hydrogenation reactions, and that these two types of CORs therefore cause committed steps for BChls a and(More)
The parental structure of bacteriochlorophyll a, bacteriochlorin, is formed by a sequential operation of two nitrogenase-like enzymes, dark-operative protochlorophyllide oxidoreductase (DPOR) and chlorophyllide a oxidoreductase (COR). Both DPOR and COR consist of two components, Fe protein and MoFe protein cognates. Here we determined kinetic parameters of(More)