Kinbara Research Group

Research

Living organisms are composed of biomolecules having various functions, and give us lots of clues how to design functional organic molecules. For examples, biological molecular machines play various roles in chemical syntheses, transportation and signal transduction through physical motions in response to stimuli, and demonstrate ultimate functions that synthetic molecules potentially possess.
By focusing on such sophisticated functions of biomolecules and their working mechanisms, our group challenges to synthesize organic molecules which have novel functions or are able to control the activity of biomolecules. As an alternative approach, we chemically modify biomolecules to develop unique functional molecules combining advantages of bio and synthetic molecules.

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1. Development of Synthetic Ion Channels

We have developed a series of multiblock amphiphiles that are composed of hydrophilic poly(ethylene glycol) chains and hydrophobic aromatic units.  These molecules self-assemble within lipid bilayer membranes and form transmembrane ion channels that are responsive to ligand bindings or mechanical stress.

Mechano-Sensitive Synthetic Ion Channels
Takahiro Muraoka, Kaori Umetsu, Kazuhito Tabata, Tsutomu Hamada, Hiroyuki Noji, Takashi Yamashita, and Kazushi Kinbara
J. Am. Chem. Soc2017, 139, 18016–18023 (10.1021/jacs.7b09515).

Reversible Ion Transportation Switch by a Ligand-Gated Synthetic Supramolecular Ion Channel
Takahiro Muraoka, Takahiro Endo, Kazuhito V. Tabata, Hiroyuki Noji, Satoru Nagatoishi, Kouhei Tsumoto, Rui Li and Kazushi Kinbara
J. Am. Chem. Soc. 2014, 136, 15584–15595.

Ion Permeation by a Folded Multiblock Amphiphilic Oligomer Achieved by Hierarchical Construction of Self-Assembled Nanopores
Takahiro Muraoka, Tatsuya Shima, Tsutomu Hamada, Masamune Morita, Masahiro Takagi, Kazuhito V. Tabata, Hiroyuki Noji, and Kazushi Kinbara
J. Am. Chem. Soc. 2012134, 19788–19794.

Mimicking Multipass Transmembrane Proteins: Synthesis, Assembly and Folding of Alternating Amphiphilic Multiblock Molecules in Liposomal Membranes
Takahiro Muraoka, Tatsuya Shima, Tsutomu Hamada, Masamune Morita, Masahiro Takagi, and Kazushi Kinbara
Chem. Commun. 201147, 194–196. [Selected as a Hot Article]

2. Development of “Structured” Poly(ethylene glycol)

Poly(ethylene glycol) (PEG) is a polydispersed polymer commonly used in biomedical applications.  Our research group has developed a series of monodispersed PEGs that are “structured” into polygonal shapes.  We discovered that structured PEGs show different physical properties compared to linear PEGs.  Furthermore, structured PEGs interact with biomolecules and improve their stabilities.

Synthesis and Thermal Responses of Polygonal Poly(ethylene glycol) Analogues
Shunichi Kawasaki, Takahiro Muraoka, Tsutomu Hamada, Kazuki Shigyou, Fumi Nagatsugi and Kazushi Kinbara
Chem. Asian J. 2016, 11, 1028–1035.

Protein Stabilization by an Amphiphilic Short Monodisperse Oligo(ethylene glycol)
Nabanita Sadhukhan, Takahiro Muraoka, Mihoko Ui, Satoru Nagatoishi, Kouhei Tsumoto, and Kazushi Kinbara
Chem. Commun. 2015, 51, 8457–8460.

Thermodriven Micrometer-Scale Aqueous-Phase Separation of Amphiphilic Oligoethylene Glycol Analogues
Shunichi Kawasaki, Takahiro Muraoka, Haruki Obara, Takerou Ishii, Tsutomu Hamada and Kazushi Kinbara
Chem. Asian J. 2014, 9, 2778–2788 (Selected as the Back Cover).

Thermal-Aggregation Suppression of Proteins by a Structured PEG Analogue: Importance of Denaturation Temperature for Effective Aggregation Suppression
Takahiro Muraoka, Nabanita Sadhukhan, Mihoko Ui, Shunichi Kawasaki, Enrikko Hazemi, Kota Adachi, and Kazushi Kinbara
Biochem. Eng. J. 2014, 86C, 41–48.

A Structured Monodisperse PEG for the Effective Suppression of Protein Aggregation
Takahiro Muraoka, Kota Adachi, Mihoko Ui, Shunichi Kawasaki, Nabanita Sadhukhan, Haruki Obara, Hidehito Tochio, Masahiro Shirakawa, and Kazushi Kinbara
Angew. Chem., Int. Ed. 201352, 2430–2434. [Selected as a “Very Important Paper (VIP)” and a Back Cover]

3. Development of Novel Protein Functionalization Methods

Enzymatically cleavable traceless biotin tags for protein PEGylation and purification
Adam M. Wawro, Yusuke Aoki, Takahiro Muraoka, Kouhei Tsumoto and Kazushi Kinbara
Chem. Commun., 2018, 54, 1913–1916 (10.1039/C7CC05814D).

Please see our Publications for details.

Completed Projects

4. Development of Synthetic Molecular Machines

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Toward Long-Distance Mechanical Communication: Studies on a Ternary Complex Interconnected by a Bridging Rotary Module
Hiroyuki Kai, Shinji Nara, Kazushi Kinbara, and Takuzo Aida
J. Am. Chem. Soc. 2008, 130, 6725–6727.

Toward Autonomously Operating Molecular Machines Driven by Transition-Metal Catalyst
Kenichi Tanaka and Kazushi Kinbara
Mol. BioSyst. 2008, 4, 512–514. [Emerging Investigators Issue, Highlighted in Chemical Science.]

Chiral Ferrocenes as Novel Rotary Modules for Molecular Machines
Kazushi Kinbara, Takahiro Muraoka, and Takuzo Aida
Org. Biomol. Chem. 2008, 1871–1876. [Selected as “Emerging Area” and “Front Cover”; The Top 10 Downloaded Articles in May 2008.]

Reversible Operation of Chiral Molecular Scissors by Redox and UV Light
Takahiro Muraoka, Kazushi Kinbara, and Takuzo Aida
Chem. Commun. 2007, 1441–1443.

Crystallographic and Chiroptical Studies on Tetraarylferrocenes for Use as Chiral Rotary Modules for Molecular Machines
Takahiro Muraoka, Kazushi Kinbara, Atsushi Wakamiya, Shigehiro Yamaguchi, and Takuzo Aida
Chem.–Eur. J. 2007, 13, 1724–1730.

A Self-Locking Molecule Operative with a Photoresponsive Key
Takahiro Muraoka, Kazushi Kinbara, and Takuzo Aida
J. Am. Chem. Soc. 2006, 128, 11600–11605.

Mechanical Twisting of a Guest by a Photoresponsive Host
Takahiro Muraoka, Kazushi Kinbara, and Takuzo Aida
Nature 2006, 440, 512–515. [Highlighted in Angewandte Chemie, C&EN, Nanotechweb.org, Newscientist and Photonics.com.]

Toward Intelligent Molecular Machines: Directed Motions of Biological and Artificial Molecules and Assemblies
Kazushi Kinbara and Takuzo Aida
Chem. Rev. 2005, 105, 1377–1400.

Light-Driven Open-Close Motion of Chiral Molecular Scissors
Takahiro Muraoka, Kazushi Kinbara, Yuka Kobayashi, and Takuzo Aida
J. Am. Chem. Soc. 2003, 125, 5612–5613. [Highlighted in Newscientist.]

5. Protein Functionalizations through Synthetic Chemical Approach

A Tubular Biocontainer: Metal Ion–Induced 1D Assembly of a Molecularly Engineered Chaperonin
Shuvendu Biswas, Kazushi Kinbara, Nobuhiro Oya, Noriyuki Ishii, Hideki Taguchi, and Takuzo Aida
J. Am. Chem. Soc. 2009, 131, 7556–7557.

Semibiological Molecular Machine with an Impremented “AND” Logic Gate for Regulation of Protein Folding
Shinichi Muramatsu, Kazushi Kinbara, Hideki Taguchi, Noriyuki Ishii, and Takuzo Aida
J. Am. Chem. Soc. 2006, 128, 3764–3769.

Toward Intelligent Molecular Machines: Directed Motions of Biological and Artificial Molecules and Assemblies
Kazushi Kinbara and Takuzo Aida
Chem. Rev. 2005, 105, 1377–1400.

Chaperonin-Mediated Stabilization and ATP-Triggered Release of Semiconductor Nanoparticles
Daisuke Ishii, Kazushi Kinbara, Yasuhiro Ishida, Noriyuki Ishii, Mina Okochi, Masafumi Yohda, and Takuzo Aida
Nature 2003, 423, 628–632. [Highlighted in Nature, C&EN, TRNmag.com, and Nanotechweb.org.]