KIKUKAWA TakashiAssociate Professor

Laboratory of Biological Information Analysis Science
Research Theme
Understanding the molecular mechanism of membrane proteins and their functional modifications for useful applications
Research Keywords

Photoactive proteins, photobiology, rhodopsin, optogenetics, directed molecular evolution, membrane protein, ion pump, membrane transport, transporter

Overview of Research

Many proteins express their respective functions by changing their conformations stepwisely. Reflecting these features, proteins are sometimes described as “molecular machines”. We are interested in the mechanism of how proteins can work like a machine, and are conducting research to elucidate the mechanism. A group of proteins called “photoreceptor proteins” has very useful properties for investigating these mechanisms. Among the photoreceptor proteins, we are particularly interested in a protein called microbial rhodopsin.

Most organisms have developed “photoreceptive proteins” to utilize sunlight as a source of information or energy. Among them, microbial rhodopsin is the most widely distributed protein in nature and has undergone diverse molecular evolution. Upon light stimulation, microbial rhodopsin changes its conformation stepwisely if it were a machine and exhibit its own function. This “light-activated” property of microbial rhodopsin makes it an excellent model protein for detecting stepwise structural changes with time-resolved measurements. We are using this property to elucidate the mechanism of microbial rhodopsin in detail. In addition to this basic research, we are also interested in the application of microbial rhodopsin to environmental problems and medical fields. By modifying the function of microbial rhodopsin or collaborating it with other proteins, we aim to develop proteins and protein complexes with useful functions.



Proteins are the chief actors on the biological phenomena. Why do these small molecules have high ability comparable to the artificial devices? We hope to find an answer to the question through the research on the functional mechanism of proteins.

Representative Publications



<Office Hour>
– Time: Anytime during the lecture period
– Place: Science Bldg. No.2, 8F, #2-806
Please contact in advance by E-mail.
E-mail: kikukawa[at]