Keio University · Chemistry
Professor Daisuke Takahashi's research lab specializes in the development of innovative synthetic methodologies in organic and peptide chemistry, with a focus on efficient and scalable peptide synthesis using novel protecting group strategies and solvent-based isolation techniques. The lab also investigates the molecular mechanisms underlying innate immune responses in insects, particularly the role of pattern recognition proteins and serine protease cascades in pathogen detection. Additionally, the lab explores the stereoselective synthesis of complex carbohydrates and the physical properties of quantum materials, such as rare-earth intermetallic compounds near absolute zero. These interdisciplinary efforts bridge synthetic chemistry, biochemistry, and materials science to address challenges in drug discovery, glycobiology, and quantum phenomena.
Figures are computed from collected data and may differ slightly.
We previously reported an efficient peptide synthesis method, AJIPHASE®, that comprises repeated reactions and isolations by precipitation. This method utilizes an anchor molecule with long-chain alkyl groups as a protecting group for the C-terminus. To further improve this method, we developed a one-pot synthesis of a peptide sequence wherein the synthetic intermediates were isolated by solvent extraction instead of precipitation. A branched-chain anchor molecule was used in the new process, si
An efficient method for the synthesis of peptides bearing an amide at the C-terminal is described. This method involves the attachment of a C-terminal protecting group bearing long aliphatic chains, followed by the repetition of simple reaction and precipitation steps with the combined advantages of liquid-phase peptide synthesis (LPPS) and solid-phase peptide synthesis (SPPS). Using this method, a hydrophobic peptide was successfully synthesized in good yield and high purity, which cannot be ob
The autoactivation of an initiating serine protease upon binding of pattern recognition proteins to pathogen surfaces is a crucial step in eliciting insect immune responses such as the activation of Toll and prophenoloxidase pathways. However, the molecular mechanisms responsible for autoactivation of the initiating protease remains poorly understood. Here, we investigated the molecular basis for the autoactivation of hemolymph protease 14 (HP14), an initiating protease in hemolymph of Manduca s
The magnetic properties of ${\mathrm{CeRu}}_{2}{\mathrm{Si}}_{2}$ at microkelvin temperatures (down to $170\ensuremath{\mu}\mathrm{K})$ and ultrasmall magnetic fields $(0.02\ensuremath{\sim}6.21\mathrm{mT})$ are investigated experimentally. The simultaneously measured ac susceptibility and static magnetization show neither evidence of the magnetic ordering, superconductivity down to the lowest temperatures nor conventional Landau Fermi-Liquid behavior. The results imply the magnetic transition t
Insect β-glucan recognition protein (βGRP), a pathogen recognition receptor for innate immune responses, detects β-1,3-glucan on fungal surfaces via its N-terminal carbohydrate-binding domain (N-βGRP) and triggers serine protease cascades for the activation of prophenoloxidase (pro-PO) or Toll pathways. Using biophysical and biochemical methods, we characterized the interaction of the N-terminal domain from Manduca sexta βGRP2 (N-βGRP2) with laminarin, a soluble form of β-1,3-glucan. We found th
Regio- and 1,2-<i>cis</i>-α-stereoselective glycosylations were investigated using 1,2-anhydroglucose donors and <i>trans</i>-1,2-diol sugar acceptors in the presence of a diboron catalyst. The reactions proceeded smoothly to provide the corresponding 1,2-<i>cis</i>-α-glycosides with consistently very high stereoselectivity and were regioselectivity controlled by the protecting groups of the acceptor. The present glycosylation method was applied successfully to the efficient synthesis of α-1,3-g
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